A child restraint system for transporting a child within an automotive vehicle includes a weight sensor for determining the weight of the child and compares the child's weight to a recommended weight range. The weight sensor is disposed within a cushion that lines a shell and provides an electrical signal to a control unit. The control unit processes the electrical signal and provides an alert signal when the weight is not within the recommended range. Also, the child restraint system may include a second sensor for sensing a condition that depends upon the child's weight such as directional orientation or angular orientation of the child restraint system, or location or tension of a vehicle seat belt or tether that secures the child restraint system within the vehicle, or the location or tension of a harness for restraining the child occupant within the child restraint system.