Mucus in the lungs or chest congestion in infants can be caused by multiple factors. Your infant is just starting to breath and can be more prone to respiratory infections. Respiratory infections cause mucus to form in the lungs and respiratory tract; mucus is a normal symptom of the common cold.

If your child has a broken leg, he may be on strict bed rest or he may be able to get around, but slowly, on crutches. Whatever the doctor’s orders are, a child with a broken leg is limited. However, it isn’t hard to find activities for him -- it just requires a little thought, creativity and preparation.

Bullying, hitting, biting and issuing demands are aggressive behaviors that elicit attention and concern from parents and caregivers.

Caloric requirements vary for infants, depending on a variety of factors such as current weight, body composition, birth weight, activity level, medical conditions, age and gender.

The American Academy of Pediatrics recommends starting solids with rice cereal, then moving to oatmeal and the introducing pureed vegetables. However, the specific time frame for introduction varies based on your individual baby's needs.

As a breastfeeding mother, taking good care of your health helps to ensure the health of your baby. Dehydration due to illness, weather or your busy lifestyle can lead to problems in the breastfeeding relationship with your baby.

Gas is most often caused by an infant swallowing too much air while feeding. However, the type of formula you are using may be causing your little one unwanted stomach distress.

Healthy people pass gas as many as 23 times every day, according to the National Digestive Diseases Information Clearinghouse. Breastfeeding mothers who make healthy dietary changes or who use supplements to increase their milk supply sometimes suffer from a gassy stomach as a result of their efforts.

Since infants can't talk, it's difficult to determine exactly what is hurting them. However, your infant's body language may give you a clue. Headaches can be minor or the symptom of a more serious illness or injury. If you cannot manage the pain on your own, you should seek the medical advice of your physician.

Due to increasing amounts of sex hormones during and after puberty, boys and girls grow considerably during their teenage years, according to the website Kids Health. While girls tend to begin these growth spurts earlier, boys tend to grow taller and over a longer period of time.

Despite the lack of development in their bodies, babies are born with heads that are at an advanced stage of development. As the brain reaches half of its adult size by 9 months and nearly three-quarters by two years of age, a baby's head must be large and grow rapidly to accommodate the rest of the body's growth.

If your baby is teething and has blisters on their tongue, it could be caused by one of several conditions. Fever or a skin rash may accompany blisters in a baby’s mouth if they have a virus. Blisters can also be the result of biting the tongue or salivary gland blockage.