diff --git a/src/baby_monitor/main.py b/src/baby_monitor/main.py
index c4082dc..1d6a848 100644
--- a/src/baby_monitor/main.py
+++ b/src/baby_monitor/main.py
@@ -12,6 +12,7 @@ from fastapi.staticfiles import StaticFiles
 from baby_monitor.routers.auth import router as auth_router
 from baby_monitor.routers.auth import verify_token
 from baby_monitor.routers.admin import router as admin_router
+from baby_monitor.routers.child import router as child_router
 from baby_monitor.routers.health import router as health_router
 from baby_monitor.repositories.dependencies.get_database import init_db
 
@@ -47,6 +48,7 @@ app.mount("/static", StaticFiles(directory=str(static_path)), name="static")
 # Include routers
 app.include_router(auth_router)
 app.include_router(admin_router)
+app.include_router(child_router)
 app.include_router(health_router)
 
 
@@ -75,6 +77,12 @@ def serve_admin() -> FileResponse:
     return FileResponse(static_path / "admin.html")
 
 
+@app.get("/add-child.html", include_in_schema=False)
+def serve_add_child() -> FileResponse:
+    """Serve the add child page."""
+    return FileResponse(static_path / "add-child.html")
+
+
 @app.get("/api/")
 def read_root(token: Annotated[str, Depends(verify_token)]) -> dict:
     """API root endpoint (requires authentication)."""
diff --git a/src/baby_monitor/models/child.py b/src/baby_monitor/models/child.py
new file mode 100644
index 0000000..86096e7
--- /dev/null
+++ b/src/baby_monitor/models/child.py
@@ -0,0 +1,23 @@
+"""Child-related request and response models."""
+
+from datetime import datetime
+from pydantic import BaseModel, Field
+
+
+class CreateChildRequest(BaseModel):
+    """Request model for creating a child."""
+
+    name: str = Field(..., min_length=1, max_length=100)
+    birth_time: datetime
+    birth_weight: float = Field(..., gt=0, description="Birth weight in grams")
+
+
+class ChildResponse(BaseModel):
+    """Response model for child data."""
+
+    id: int
+    name: str
+    birth_time: datetime
+    birth_weight: float
+    user_id: int
+    created_at: datetime
diff --git a/src/baby_monitor/models/db/child.py b/src/baby_monitor/models/db/child.py
new file mode 100644
index 0000000..7a633ae
--- /dev/null
+++ b/src/baby_monitor/models/db/child.py
@@ -0,0 +1,28 @@
+"""Child database model."""
+
+from typing import TYPE_CHECKING
+from sqlalchemy import Column, Integer, String, DateTime, Float, ForeignKey
+from datetime import datetime
+
+if TYPE_CHECKING:
+    from sqlalchemy.orm import DeclarativeBase
+
+    Base = DeclarativeBase
+else:
+    from baby_monitor.repositories.dependencies.get_database import Base
+
+
+class Child(Base):
+    """Child database model."""
+
+    __tablename__ = "children"
+
+    id = Column(Integer, primary_key=True, index=True)
+    name = Column(String, nullable=False)
+    birth_time = Column(DateTime, nullable=False)
+    birth_weight = Column(Float, nullable=False)  # in grams
+    user_id = Column(Integer, ForeignKey("users.id"), nullable=False)
+    created_at = Column(DateTime, default=datetime.utcnow, nullable=False)
+
+    def __repr__(self) -> str:
+        return f"<Child(id={self.id}, name='{self.name}', user_id={self.user_id})>"
diff --git a/src/baby_monitor/repositories/child/sqlite_child.py b/src/baby_monitor/repositories/child/sqlite_child.py
new file mode 100644
index 0000000..e18d2dc
--- /dev/null
+++ b/src/baby_monitor/repositories/child/sqlite_child.py
@@ -0,0 +1,111 @@
+"""SQLite implementation of child repository."""
+
+from datetime import datetime
+from sqlalchemy.orm import Session
+
+from baby_monitor.repositories.interfaces.child_repository_interface import (
+    ChildRepositoryInterface,
+)
+from baby_monitor.models.db.child import Child
+
+
+class SQLiteChildRepository(ChildRepositoryInterface):
+    """SQLite implementation for child data access."""
+
+    def __init__(self, db: Session):
+        self.db = db
+
+    def create(
+        self, name: str, birth_time: datetime, birth_weight: float, user_id: int
+    ) -> dict:
+        """Create a new child record."""
+        child = Child(
+            name=name,
+            birth_time=birth_time,
+            birth_weight=birth_weight,
+            user_id=user_id,
+        )
+        self.db.add(child)
+        self.db.commit()
+        self.db.refresh(child)
+
+        return {
+            "id": child.id,
+            "name": child.name,
+            "birth_time": child.birth_time,
+            "birth_weight": child.birth_weight,
+            "user_id": child.user_id,
+            "created_at": child.created_at,
+        }
+
+    def get_by_id(self, child_id: int) -> dict | None:
+        """Get a child by ID."""
+        child = self.db.query(Child).filter(Child.id == child_id).first()
+        if not child:
+            return None
+
+        return {
+            "id": child.id,
+            "name": child.name,
+            "birth_time": child.birth_time,
+            "birth_weight": child.birth_weight,
+            "user_id": child.user_id,
+            "created_at": child.created_at,
+        }
+
+    def get_by_user_id(self, user_id: int) -> list[dict]:
+        """Get all children for a specific user."""
+        children = self.db.query(Child).filter(Child.user_id == user_id).all()
+
+        return [
+            {
+                "id": child.id,
+                "name": child.name,
+                "birth_time": child.birth_time,
+                "birth_weight": child.birth_weight,
+                "user_id": child.user_id,
+                "created_at": child.created_at,
+            }
+            for child in children
+        ]
+
+    def update(
+        self,
+        child_id: int,
+        name: str | None = None,
+        birth_time: datetime | None = None,
+        birth_weight: float | None = None,
+    ) -> dict | None:
+        """Update a child record."""
+        child = self.db.query(Child).filter(Child.id == child_id).first()
+        if not child:
+            return None
+
+        if name is not None:
+            child.name = name  # type: ignore[assignment]
+        if birth_time is not None:
+            child.birth_time = birth_time  # type: ignore[assignment]
+        if birth_weight is not None:
+            child.birth_weight = birth_weight  # type: ignore[assignment]
+
+        self.db.commit()
+        self.db.refresh(child)
+
+        return {
+            "id": child.id,
+            "name": child.name,
+            "birth_time": child.birth_time,
+            "birth_weight": child.birth_weight,
+            "user_id": child.user_id,
+            "created_at": child.created_at,
+        }
+
+    def delete(self, child_id: int) -> bool:
+        """Delete a child record."""
+        child = self.db.query(Child).filter(Child.id == child_id).first()
+        if not child:
+            return False
+
+        self.db.delete(child)
+        self.db.commit()
+        return True
diff --git a/src/baby_monitor/repositories/dependencies/get_child_repository.py b/src/baby_monitor/repositories/dependencies/get_child_repository.py
new file mode 100644
index 0000000..a5d677b
--- /dev/null
+++ b/src/baby_monitor/repositories/dependencies/get_child_repository.py
@@ -0,0 +1,15 @@
+"""Dependency for getting child repository instance."""
+
+from typing import Annotated
+from fastapi import Depends
+from sqlalchemy.orm import Session
+
+from baby_monitor.repositories.dependencies.get_database import get_database
+from baby_monitor.repositories.child.sqlite_child import SQLiteChildRepository
+
+
+def get_child_repository(
+    db: Annotated[Session, Depends(get_database)],
+) -> SQLiteChildRepository:
+    """Get child repository instance."""
+    return SQLiteChildRepository(db)
diff --git a/src/baby_monitor/repositories/dependencies/get_database.py b/src/baby_monitor/repositories/dependencies/get_database.py
index 6f465e1..ec35bcf 100644
--- a/src/baby_monitor/repositories/dependencies/get_database.py
+++ b/src/baby_monitor/repositories/dependencies/get_database.py
@@ -77,6 +77,7 @@ def init_db() -> None:
     # Import models to register them with Base.metadata
     # This must be done before create_all() is called
     from baby_monitor.models.db.user import User  # noqa: F401
+    from baby_monitor.models.db.child import Child  # noqa: F401
     from baby_monitor.models.invitation import Invitation  # noqa: F401
 
     # Ensure data directory exists
diff --git a/src/baby_monitor/repositories/interfaces/child_repository_interface.py b/src/baby_monitor/repositories/interfaces/child_repository_interface.py
new file mode 100644
index 0000000..0f04844
--- /dev/null
+++ b/src/baby_monitor/repositories/interfaces/child_repository_interface.py
@@ -0,0 +1,36 @@
+"""Interface for child repository operations."""
+
+from abc import ABC, abstractmethod
+from datetime import datetime
+
+
+class ChildRepositoryInterface(ABC):
+    """Interface for child data access operations."""
+
+    @abstractmethod
+    def create(
+        self, name: str, birth_time: datetime, birth_weight: float, user_id: int
+    ) -> dict:
+        """Create a new child record."""
+
+    @abstractmethod
+    def get_by_id(self, child_id: int) -> dict | None:
+        """Get a child by ID."""
+
+    @abstractmethod
+    def get_by_user_id(self, user_id: int) -> list[dict]:
+        """Get all children for a specific user."""
+
+    @abstractmethod
+    def update(
+        self,
+        child_id: int,
+        name: str | None = None,
+        birth_time: datetime | None = None,
+        birth_weight: float | None = None,
+    ) -> dict | None:
+        """Update a child record."""
+
+    @abstractmethod
+    def delete(self, child_id: int) -> bool:
+        """Delete a child record."""
diff --git a/src/baby_monitor/routers/child.py b/src/baby_monitor/routers/child.py
new file mode 100644
index 0000000..718b461
--- /dev/null
+++ b/src/baby_monitor/routers/child.py
@@ -0,0 +1,90 @@
+"""Child management router."""
+
+from typing import Annotated
+from fastapi import APIRouter, HTTPException, Depends
+
+from baby_monitor.models.child import CreateChildRequest, ChildResponse
+from baby_monitor.routers.auth import verify_token
+from baby_monitor.repositories.child.sqlite_child import SQLiteChildRepository
+from baby_monitor.repositories.dependencies.get_child_repository import (
+    get_child_repository,
+)
+
+router = APIRouter(prefix="/api/children", tags=["children"])
+
+
+@router.post("", response_model=ChildResponse, status_code=201)
+def create_child(
+    request: CreateChildRequest,
+    user_id: Annotated[int, Depends(verify_token)],
+    child_repo: Annotated[SQLiteChildRepository, Depends(get_child_repository)],
+) -> ChildResponse:
+    """Create a new child for the authenticated user."""
+    child = child_repo.create(
+        name=request.name,
+        birth_time=request.birth_time,
+        birth_weight=request.birth_weight,
+        user_id=user_id,
+    )
+
+    return ChildResponse(**child)
+
+
+@router.get("", response_model=list[ChildResponse])
+def get_user_children(
+    user_id: Annotated[int, Depends(verify_token)],
+    child_repo: Annotated[SQLiteChildRepository, Depends(get_child_repository)],
+) -> list[ChildResponse]:
+    """Get all children for the authenticated user."""
+    children = child_repo.get_by_user_id(user_id)
+    return [ChildResponse(**child) for child in children]
+
+
+@router.get("/{child_id}", response_model=ChildResponse)
+def get_child(
+    child_id: int,
+    user_id: Annotated[int, Depends(verify_token)],
+    child_repo: Annotated[SQLiteChildRepository, Depends(get_child_repository)],
+) -> ChildResponse:
+    """Get a specific child by ID."""
+    child = child_repo.get_by_id(child_id)
+
+    if not child:
+        raise HTTPException(status_code=404, detail="Child not found")
+
+    # Verify the child belongs to the authenticated user
+    if child["user_id"] != user_id:
+        raise HTTPException(status_code=403, detail="Access denied")
+
+    return ChildResponse(**child)
+
+
+@router.put("/{child_id}", response_model=ChildResponse)
+def update_child(
+    child_id: int,
+    request: CreateChildRequest,
+    user_id: Annotated[int, Depends(verify_token)],
+    child_repo: Annotated[SQLiteChildRepository, Depends(get_child_repository)],
+) -> ChildResponse:
+    """Update a child's information."""
+    # First check if child exists and belongs to user
+    child = child_repo.get_by_id(child_id)
+
+    if not child:
+        raise HTTPException(status_code=404, detail="Child not found")
+
+    if child["user_id"] != user_id:
+        raise HTTPException(status_code=403, detail="Access denied")
+
+    # Update the child
+    updated_child = child_repo.update(
+        child_id=child_id,
+        name=request.name,
+        birth_time=request.birth_time,
+        birth_weight=request.birth_weight,
+    )
+
+    if not updated_child:
+        raise HTTPException(status_code=500, detail="Update failed")
+
+    return ChildResponse(**updated_child)
diff --git a/src/baby_monitor/static/add-child.html b/src/baby_monitor/static/add-child.html
new file mode 100644
index 0000000..7fde252
--- /dev/null
+++ b/src/baby_monitor/static/add-child.html
@@ -0,0 +1,322 @@
+<!doctype html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>Add Child - Baby Monitor</title>
+    <style>
+      * {
+        margin: 0;
+        padding: 0;
+        box-sizing: border-box;
+      }
+
+      body {
+        font-family:
+          -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu,
+          Cantarell, sans-serif;
+        background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
+        min-height: 100vh;
+        display: flex;
+        justify-content: center;
+        align-items: center;
+        padding: 20px;
+      }
+
+      .container {
+        background: white;
+        border-radius: 12px;
+        box-shadow: 0 10px 40px rgba(0, 0, 0, 0.2);
+        padding: 40px;
+        max-width: 500px;
+        width: 100%;
+      }
+
+      h1 {
+        color: #333;
+        margin-bottom: 10px;
+        font-size: 28px;
+      }
+
+      .subtitle {
+        color: #666;
+        margin-bottom: 30px;
+        font-size: 14px;
+      }
+
+      .form-group {
+        margin-bottom: 20px;
+      }
+
+      label {
+        display: block;
+        margin-bottom: 8px;
+        color: #333;
+        font-weight: 600;
+        font-size: 14px;
+      }
+
+      input {
+        width: 100%;
+        padding: 12px;
+        border: 1px solid #ddd;
+        border-radius: 6px;
+        font-size: 14px;
+        transition: border-color 0.2s;
+      }
+
+      input:focus {
+        outline: none;
+        border-color: #667eea;
+      }
+
+      .button {
+        background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
+        color: white;
+        border: none;
+        padding: 12px 24px;
+        border-radius: 6px;
+        font-size: 16px;
+        font-weight: 600;
+        cursor: pointer;
+        transition:
+          transform 0.2s,
+          box-shadow 0.2s;
+        width: 100%;
+        margin-top: 10px;
+      }
+
+      .button:hover {
+        transform: translateY(-2px);
+        box-shadow: 0 4px 12px rgba(102, 126, 234, 0.4);
+      }
+
+      .button:active {
+        transform: translateY(0);
+      }
+
+      .button:disabled {
+        opacity: 0.6;
+        cursor: not-allowed;
+        transform: none;
+      }
+
+      .button.secondary {
+        background: #6c757d;
+        margin-top: 10px;
+      }
+
+      .button.secondary:hover {
+        box-shadow: 0 4px 12px rgba(108, 117, 125, 0.4);
+      }
+
+      .message {
+        padding: 12px;
+        border-radius: 6px;
+        margin-bottom: 20px;
+        display: none;
+      }
+
+      .message.show {
+        display: block;
+      }
+
+      .message.error {
+        background: #ffebee;
+        border-left: 4px solid #f44336;
+        color: #c62828;
+      }
+
+      .message.success {
+        background: #e8f5e9;
+        border-left: 4px solid #4caf50;
+        color: #2e7d32;
+      }
+
+      .help-text {
+        font-size: 12px;
+        color: #666;
+        margin-top: 4px;
+      }
+    </style>
+  </head>
+  <body>
+    <div class="container">
+      <h1>👶 Add Child</h1>
+      <p class="subtitle">Enter your child's information</p>
+
+      <div id="message" class="message"></div>
+
+      <form id="addChildForm">
+        <div class="form-group">
+          <label for="name">Child's Name *</label>
+          <input
+            type="text"
+            id="name"
+            name="name"
+            required
+            placeholder="Enter child's name"
+            maxlength="100"
+          />
+        </div>
+
+        <div class="form-group">
+          <label for="birthTime">Date and Time of Birth *</label>
+          <input
+            type="datetime-local"
+            id="birthTime"
+            name="birthTime"
+            required
+          />
+          <p class="help-text">
+            Select the date and time when your child was born
+          </p>
+        </div>
+
+        <div class="form-group">
+          <label for="birthWeight">Birth Weight (grams) *</label>
+          <input
+            type="number"
+            id="birthWeight"
+            name="birthWeight"
+            required
+            min="1"
+            step="1"
+            placeholder="e.g., 3500"
+          />
+          <p class="help-text">Enter weight in grams (1 kg = 1000 grams)</p>
+        </div>
+
+        <button type="submit" class="button" id="submitBtn">Add Child</button>
+        <button type="button" class="button secondary" onclick="goBack()">
+          Cancel
+        </button>
+      </form>
+    </div>
+
+    <script>
+      // Check if user is authenticated
+      const token = localStorage.getItem("access_token");
+      if (!token) {
+        window.location.href = "/login.html";
+      }
+
+      // Get child ID from URL if editing
+      const urlParams = new URLSearchParams(window.location.search);
+      const childId = urlParams.get("id");
+      const isEditMode = !!childId;
+
+      const form = document.getElementById("addChildForm");
+      const messageDiv = document.getElementById("message");
+      const submitBtn = document.getElementById("submitBtn");
+
+      // Update page title and button text if editing
+      if (isEditMode) {
+        document.querySelector("h1").textContent = "✏️ Edit Child";
+        document.querySelector(".subtitle").textContent =
+          "Update your child's information";
+        submitBtn.textContent = "Update Child";
+
+        // Load existing child data
+        loadChildData(childId);
+      }
+
+      async function loadChildData(id) {
+        try {
+          const response = await fetch(`/api/children/${id}`, {
+            headers: {
+              Authorization: `Bearer ${token}`,
+            },
+          });
+
+          if (response.ok) {
+            const child = await response.json();
+
+            // Populate form fields
+            document.getElementById("name").value = child.name;
+
+            // Format datetime for datetime-local input
+            const birthDate = new Date(child.birth_time);
+            const formattedDate = birthDate.toISOString().slice(0, 16);
+            document.getElementById("birthTime").value = formattedDate;
+
+            document.getElementById("birthWeight").value = child.birth_weight;
+          } else {
+            showMessage("Failed to load child data", "error");
+          }
+        } catch (error) {
+          showMessage("Error loading child data", "error");
+        }
+      }
+
+      form.addEventListener("submit", async (e) => {
+        e.preventDefault();
+
+        const name = document.getElementById("name").value;
+        const birthTime = document.getElementById("birthTime").value;
+        const birthWeight = parseFloat(
+          document.getElementById("birthWeight").value,
+        );
+
+        // Disable button during request
+        submitBtn.disabled = true;
+        const originalText = submitBtn.textContent;
+        submitBtn.textContent = isEditMode ? "Updating..." : "Adding...";
+        messageDiv.classList.remove("show");
+
+        try {
+          const url = isEditMode ? `/api/children/${childId}` : "/api/children";
+          const method = isEditMode ? "PUT" : "POST";
+
+          const response = await fetch(url, {
+            method: method,
+            headers: {
+              "Content-Type": "application/json",
+              Authorization: `Bearer ${token}`,
+            },
+            body: JSON.stringify({
+              name: name,
+              birth_time: birthTime,
+              birth_weight: birthWeight,
+            }),
+          });
+
+          const data = await response.json();
+
+          if (response.ok) {
+            showMessage(
+              isEditMode
+                ? "Child updated successfully!"
+                : "Child added successfully!",
+              "success",
+            );
+            // Redirect to home page after 1 second
+            setTimeout(() => {
+              window.location.href = "/";
+            }, 1000);
+          } else {
+            showMessage(
+              data.detail ||
+                `Failed to ${isEditMode ? "update" : "add"} child. Please try again.`,
+              "error",
+            );
+          }
+        } catch (error) {
+          showMessage("Network error. Please try again.", "error");
+        } finally {
+          submitBtn.disabled = false;
+          submitBtn.textContent = originalText;
+        }
+      });
+
+      function showMessage(text, type) {
+        messageDiv.textContent = text;
+        messageDiv.className = `message ${type} show`;
+      }
+
+      function goBack() {
+        window.location.href = "/";
+      }
+    </script>
+  </body>
+</html>
diff --git a/src/baby_monitor/static/index.html b/src/baby_monitor/static/index.html
index da17c70..0bbdb36 100644
--- a/src/baby_monitor/static/index.html
+++ b/src/baby_monitor/static/index.html
@@ -129,6 +129,7 @@
     <div class="menu-backdrop" id="menuBackdrop"></div>
 
     <div class="menu-overlay" id="menuOverlay">
+      <div class="menu-item" id="menuAddChild">👶 Add Child</div>
       <div class="menu-item logout" id="menuLogout">🚪 Logout</div>
     </div>
 
@@ -160,6 +161,10 @@
       burgerMenu.addEventListener("click", toggleMenu);
       menuBackdrop.addEventListener("click", closeMenu);
 
+      document.getElementById("menuAddChild").addEventListener("click", () => {
+        window.location.href = "/add-child.html";
+      });
+
       document.getElementById("menuLogout").addEventListener("click", () => {
         closeMenu();
         logout();
@@ -187,14 +192,29 @@
             }
           })
           .then((user) => {
-            // Show authenticated content
-            document.getElementById("content").innerHTML = `
+            // Check if user has any children
+            return fetch("/api/children", {
+              headers: {
+                Authorization: `Bearer ${token}`,
+              },
+            })
+              .then((response) => response.json())
+              .then((children) => {
+                // If no children, redirect to add-child page
+                if (children.length === 0) {
+                  window.location.href = "/add-child.html";
+                  return;
+                }
+
+                // Show authenticated content
+                document.getElementById("content").innerHTML = `
                     <h1>Welcome to Baby Monitor!</h1>
                     <div class="user-info">
                         <p><strong>Logged in as:</strong> ${username}</p>
                     </div>
                     <p>Your session is active.</p>
                 `;
+              });
           })
           .catch((error) => {
             console.error("Error:", error);