But again, valid point. When I was young years ago I had all the sites memorized with their averages listed as I strolled through the years of puberty. Illustration of a super children smiling happy while wearing capes against ray light background for copy space. Gonadotropin and sex steroid levels fall to low levels nearly undetectable by current clinical assays for approximately another 8 to 10 years of childhood. August 10, Reply. The gonads testes and ovaries respond to rising levels of LH and FSH by producing the steroid sex hormones , testosterone and estrogen. In general, girls younger than boys.