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Farid
Gazizov

Impact
of evolution on human thought

Testosterone

For a long period of time humans could not answer the
question of what makes a man, a man, and a women, a women.  As was recently
found main difference is not just in presence of genitals.  Probably one will
ask why?  The answer is that genitals themselves are indirect products of
another matter.  The name of this matter is testosterone. 


“Testosterone is a hormone that stimulates sexual
development in male human beings.  It belongs to a family of hormones called
androgens.  Primarily the testicles, a part of male sex glands, produce
androgens.  The ovaries in females and the adrenal glands in both sexes also
yield small amounts of testosterone and other androgens (The world book
encyclopedia).”


In its earliest crucial functions, in developing
embryo, testosterone play the key role in telling the cells of the genetically
male embryo to develop as a male.  It is amazing, but all human embryo begins
as females for the first few weeks of an embryo’s life, a small group of cells
have potential to develop either as ovaries or testes.  About one million of
genes that are needed to direct the development of a human being, one single
gene (the “SRY” gene), which is carried on the Y chromosome, is responsible for
determining the sex of the embryo.  If the embryo’s cells contain the “SRY”
gene, the embryo will develop testes, which at some point and for a limited
period of time early in its development produce and release a big amount of
testosterone.   It turn, testosterone then signal the cells of other parts of
the embryo to develop as a male. 




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