A hand-held pediatric medical diagnostic device includes a sensor module adapted to detect one or more corresponding conditions of a child. A gel material at least partially coats a contact surface on the diagnostic device. The area of the contact surface and the weight associated therewith are selected to substantially stabilize the sensor module during use. In one version, the pediatric device comprises a pediatric respiratory rate sensing device in which an accelerometer is connected to a portable, rechargeable power source.