t h e pS
e V
The M ale Birth Control Pill
irth control pills first became available for females in the
1960s. The basis of birth control pills was to use various
combinations of estrogens and progesterone to “fool" the body
into thinking that it is pregnant. The hormones in birth control
pills suppress follicle development and ovulation without altering
sexual desire. If it works so well for women, why is there no male
birth control pill? There have been several attempts to produce
such a form of male contraception, but none has achieved com-
mercial success.
One strategy is to use high doses of testosterone to sup-
press spermatogenesis. While high testosterone levels can suc-
cessfully suppress spermatogenesis
and reduce secretion of GnRH,
, and FSH through negative
feedback, they can also suppress
sexual desire and even cause
sterility. Another strategy has
been to use high concentrations
of inhibin to suppress FSH
tion, with the goal of control-
ling spermatogenesis without
affecting the LH
and testosterone
secretions that control sex drive.
However, this approach has also
met with little success.
In 2000, a new hormone
called gonadotropin-
inhibiting hormone (GnIH) was
found in birds; it suppresses
the secretion of GnRH. Recently,
GnIH was found in the human
hypothalamus and was shown to
suppress GnRH in neurons within
the laboratory. Research into this
potential new male birth control
method is currently under way.
Think Critically» 1. How could the sup-
pression of GnRH secretion suppress
2. Given what you have learned about
male reproductive hormones, how
could you invent a form of male birth
control that inhibits spermatogenesis
without altering the male sex drive?
would a couple have trouble conceiving
do intrauterine devices (iUDs) work?
if the sperm were delivered to the female 24
hours after ovulation?
Fertilization Requires the Egg and Sperm to Get Very Close to One Another
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