In the uterus during pregnancy, the male and female fetus have identical genitalia until about the eighth week after conception. Each fetus does have the genes determining whether it will be male or female from the moment of conception. One job of these genes is to determine which hormone to produce—estrogen or testosterone. In response to these hormones, the fetus’s genitals which are not yet male nor female but containing general tissue will change into male or female—the tissue closes the opening and shapes a penis and testicles outside the body in a male and it forms an internal vagina, uterus, and ovaries in the female, leaving the opening which is the entrance to the vagina.
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The same hormones (GnRH, LH and FSH) stimulate the gonads to develop and produce their own hormones in both males and females. Estrogen, progesterone, and testosterone are produced in male and female bodies. The difference is in the amount of each hormone produced.
Both males and females have cycles. During their lifetimes, both are infertile from birth until puberty. Then females are fertile from menarche until menopause (from age 10-50). Males are fertile from puberty (first ejaculation: sperm) for the rest of their lives, although sperm and hormone production decrease with age. Females have a monthly cycle producing one egg and preparing for pregnancy. They are fertile for a relatively few number of days during each cycle. Males have a 60 day cycle of hormone production: highs and lows in the amount or level of hormone produced, but they are always fertile once their bodies start producing sperm. They have a 72 day cycle for each sperm to reach maturity (activated and capacitated). They have a daily cycle where their bodies are making more testosterone during the night than in the morning. This is especially true in adolescence.
The final similarity we want to emphasize is the emotional swings at the onset of puberty and throughout adolescence which are experienced by both males and females. They feel confusion (on their own part and on the part of adults who are relating to them) about whether they are children or adults. Everyone can cope better with these feelings by learning good communication skills.