some1 wanted to know about AAS and its effect on male fertility. i dug this up for u hope it helps.
LONDON (AP) Weekly injections of testosterone reduce the sperm
count of almost all men to below the threshold needed for
conception, according to a study published today by the World
Health Organization.
The 2 1/2-year study of 399 couples in nine countries found that
the injections were an effective contraceptive for 98.6 percent,
according to the report in Fertility and Sterility, the journal of
the American Society for Reproductive Medicine.
Testosterone was already known to inhibit the production of
pituitary signals which normally instruct the testes to produce
sperm.
The men, aged 21 to 45, were all normal, healthy, fertile and in
stable relationships. They received weekly testosterone shots in
the buttocks.
There were only four pregnancies among the study couples during
the test period.
Another result of the study was discovering the sperm threshold
necessary for contraception, according to Fred Wu, a senior
lecturer in endocrinology at Manchester University who supervised
the monitoring of 72 British couples.
Earlier research had shown that testosterone injections would
virtually eliminate sperm production in 60 percent of men tested.
The problem was in inhibiting contraception among men whose sperm
level was lowered, but not wiped out, by testosterone injections.
The study showed that a sperm count of less than three million
was enough to guarantee no conception. That threshold was met by a
further 38.6 percent of the men bringing effectiveness to 98.6
percent.
``Previously we did not know what the effective threshold below
which there will not be conception,'' Wu said. ``This means the
vast majority of men can use it.''
He said it was still not known why the injections were not
efective in some men.
One American expert said the study may point to a breakthrough
in contraceptive techniques.
``It would seem a strong indication that male hormone given by
injection could be an effective contraceptive, the only drawback
being the painful method,'' said Richard Sherins, the director of
andrology at the Genetics and IVF Institute in Fairfax, Va.
``It would show that testosterone, like estrogen in a female,
can be an additional method of reproduction control,'' he said.
Wu estimated it could be between five and eight years before a
better technique of administering the method was perfected.
``It is a painful injection in the buttock. But we believe we
cam improve on that with long-acting injections, tablets, patches
and even pellet implants,'' Wu said.
The seven other participating countries, aside from Britain and
the United States, were Australia, China, Sweden, France, Hungary,
Singapore and Thailand.
The American tests were carried under the auspices of scientists
at the University of Washington in Seattle UCLA-Torrance.
