You're Much Too Young, Girl: Girls Hit Puberty at Younger Ages

Gary Puckett was ahead of his time. One of his best known songs, the 1968 classic "Young Girl," told about an older man trying to do the right thing and stay away from a much younger girl. Smart man. Over the past few years its been found that young girls are starting puberty sooner than they did a century ago, with unpleasant consequences.

There are lots of potential reason for this fact. One is the hormones put in milk. Early, or precocious puberty (I don't like that term. When I think of "precocious," I think of something adorable. Growing breasts at age 8 aint cute.) was thought in the early 1990's to be caused by an artificial bovine growth hormone called rBGH. The hormone is still in the milk and meat after it is eaten, and may have caused boys and girls (especially) to mature way too fast.

The evolutionary psychology explanation is that early puberty in girls is caused by the lack of a caring bond with her parents, particularly her father. Once again, the basic idea of evolutionary psychology is that the whole purpose of life is to pass on your genes through your children. The early puberty phenomenon is thought to be natures way of bettering the odds that a girl will get pregnant if she lives in a less than perfect environment.

Anything that may lead to a girl's premature death could possibly lead to precocious puberty. Nature is giving the girl a chance to have children before she dies. Living in a dangerous environment (such as one without a father/protector or a stable family) would possibly shorten a child's lifespan. Lack of stability could be unconsciously determined by a pre-teen girl by her mother's new husband or boyfriend. The man's pheromones would be different from her biological father's, setting her early puberty into motion.

This could be a disaster for the young woman. Those girls that grew up in stressful environments showed the following symptoms:
1. They went through puberty stages faster.
2. They had their periods about 5 months sooner than average.
3. They had sex at an earlier age.
4. They had children sooner and were less involved with them.
5. They had less stable relationships with their partners.

Sources:

http://www.livescience.com/health/070904_bad_puberty.html
http://www.psychologytoday.com/blog/the-scientific-fundamentalist/200810/why-has-the-age-puberty-declined-in-recent-decades-iii
Jones, Richard E. Human Reproductive Biology. Academic Press, 2006.