Although testosterone is commonly known as the male hormone, it actually plays an important role in the development and function of the bones, muscles, heart and blood vessels in both boys and girls. Early on, testosterone levels guide the development of male or female-linked sex organs. During adolescence, testosterone signals that it's time for boys to develop facial hair and a deep voice or for girls to develop higher-pitched voices and their own characteristic patterns of body hair.
Where It Comes From
The testosterone production cycle begins in the youngster's pituitary gland, which triggers the production of the hormone and then regulates the amount of testosterone circulating in your child's bloodstream. When testosterone levels are low, the pituitary stimulates the release of more testosterone from the adrenal gland in both boys and girls. Males also release testosterone from their testicles, while girls produce testosterone in their ovaries.
How It's Measured
If your child's doctor is concerned about the youngster's testosterone level, he may order a simple blood test to be done in a medical laboratory. It's not necessary for your child to fast before this test.
Levels in Boys
While boys have low testosterone levels during childhood, adolescence heralds the start of a rise in the hormone, says MayoClinic.com. Baby boys usually have less than 30 nanograms/deciliter, or ng/dL, in the blood, according to University of Michigan Health System. Teenage boys between the ages of 14 and 15 years typically have a testosterone blood level of 8 to 53 ng/dL and the level increases significantly to a range of 200 to 970 ng/dL from 16 to 19 years of age.
Levels in Girls
Baby girls have about 1/3 less testosterone than baby boys, typically below 10 ng/dL, says the University of Michigan Health System. Elementary school girls from 7 to 9 years of age run between 1 and 12 ng/dL and that level increases only slightly to 2 to 33 ng/dL between 10 and 13 years of age. Adolescent girls from 14 to 17 run between 8 and 53 ng/dL, which is much lower than their male classmates.
Significance
If your son is showing signs of precocious, or early, puberty, his pediatrician may order a lab test to see if he has too much testosterone in his system. Conversely, low levels of testosterone may delay male puberty. The doctor may also want to check testosterone levels if your daughter develops excessive body or facial hair or other sex-linked traits associated with males.
Considerations
Like any other laboratory test, a testosterone level is a number that needs to be evaluated by a health-care professional. If your youngster is taking steroids for conditions like asthma, his testosterone levels will be lower than normal. Children that use seizure drugs or barbiturates might have abnormally high testosterone levels, says Lab Tests Online.
