Joanna,
There are few basic differences between male and female, and most of
them are the result of differences in growth of structures rather than
differences in the structures themselves.  Even our seemingly very
different genitals come from the same buds and folds that develop a
little differently (because of hormones).  In the same way, males and
females both have mammary glands, including nipples, but female's
mammary glands grow at several important stages of life (like
adolescence and pregnancy) and those of males generally do not.  If a
male's breasts grow, it is called gynecomastia.  If given proper
hormones, or stimulation, males can produce milk, though not as much as
females.  If you want to know more about this, look in a human
embryology book.
--
Catherine Watson Genna, IBCLC  NYC  mailto:[log in to unmask]