Girls with early puberty 6 to 8 years of age with early breast development. Girls with delayed adolescence 11 to 14 years of age with bone age delay of at least 2 standard deviations and/or delay in age-appropriate pubertal development. Boys with early puberty 6 to 9 years of age with advancement of pubic hair growth.

Boys with delayed adolescence 12 to 17 years of age and bone age delay of at least 2 standard deviations and/or delay in age-appropriate pubertal development.

Children will need a weight > 20 kg and hematocrit > 34% to participate safely.

Inclusion Criteria:

Early Puberty Children who have early puberty may participate in this study. Children must be between 6 and 10 years of age and be healthy with the exception of having early puberty. For early puberty, girls should have had the onset of breast development prior to 8 years of age and boys should have the onset of pubic hair growth or genital growth prior to 9 years of age.

Inclusion Criteria for Delayed Puberty Children who have late (delayed) puberty may participate in this study. Children must be between 12 and 17 years of age and be healthy with the exception of having late puberty. In order to have late puberty, boys and girls should have short stature compared to their family with at least one year delay in bone age as determined by bone age x-ray and/or have the onset of secondary sexual characteristics (breast and pubic hair growth) at 12 years of age or later for a girl or 13 years of age or later for a boy.

Exclusion Criteria:

Early Puberty Children with known genetic disorders, chronic medical conditions requiring the use of steroids, and use of medication for puberty within the last 3 months are excluded.

Delayed Puberty Children with known genetic disorders with the exception of possible hypogonadotropic hypogonadism, chronic medical conditions requiring the use of steroids, and use of medication for puberty within the last 3 months are excluded.

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