Answer 1:
Human males start making sperm as part of
puberty—the changes people go through when they
mature.
All of the cells in a person’s body come from
the cell that was formed when their mother’s egg
cell joined with their father’s sperm cell.
After that, the cells keep dividing. Different
cells specialize into different jobs. It’s
pretty amazing that we can go from one cell into
trillions of cells of so many different types.
When males are born, they have cells that can
become sperm cells, but they are not sperm cells
yet. The cells will not start to mature until
the male is about 13 to 16 years old.
Hormones are chemicals that control many
things in our bodies. Reproduction is one of
those things. Hormones tell some cells to
divide and then tell some of them to mature. A
mature sperm cell is very small. It has DNA, a
tail that allows it to swim, some organelles to
power the tail, an outer membrane, and not much
else. Men produce about 250 million sperm a
day. As they get older, they produce fewer
sperm.
Humans today start puberty a few years
earlier than they used to. Some people think
this is because we have better nutrition or just
eat more. Others say it is because of chemicals
in our environment. How do you think scientists
might answer this question?
Thanks for asking,
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