1899
Germany's pioneering researcher Magnus Hirschfeld
writes that being gay or lesbian is biologically determined.
1991
A study of twins reveals that genes and biology are
markers for homosexuality. Researchers find that 52%
of identical twin brothers of gay men were also gay,
compared with 22% of fraternal twins and just 11% of
adoptive brothers.
1991
Simon LeVay, after studying the brains of dead gay and
straight men, publishes a paper in Science arguing
that homosexuality is biologically based. He later
expands his ideas in the 1993 book The Sexual Brain.
1993
In a major study that spurs cultural battles,
researchers say they have identified a gene pattern
that determines male homosexuality. A National Cancer
Institute geneticist suggests that a gay gene resides in
the X chromosome, which men inherit from their mothers.
1995 & 2005
A 1995 NIH study focuses on male fruit flies that began
mating with each other after their body chemistry was
changed. In June 2005, scientists in Vienna report
that a genetically altered female fruit fly attempted
to mate with another female fruit fly instead of a male,
suggesting sexual attraction is genetic.
1999
A University of Texas researcher finds that the tones
produced by the inner ears of lesbians are weaker and
not as numerous as those produced by straight women.
2000
Researchers find further evidence linking sexual
orientation with birth order. Men with same-sex
attraction seem more likely to be born later than
straight brothers in families with multiple male children.
2003
Psychologists measure eye-blink reactions after
subjecting gay and straight men and women to loud
noises. The reactions of gay and straight members of
each gender are found to be significantly different and
linked to an area of the brain that determines
sexuality. They conclude that a person's sexual
orientation is determined before birth.
2004
The same genes that make men gay may also make their
female relatives more fertile. Researchers find that
the moms, sisters, and maternal aunts of gay men often
have significantly more children than the mean--and
many of their offspring are gay or lesbian as well.
2005
A genome researcher in Chicago says he has found a group
of genes, not a single "gay gene," that
strongly affect whether a man is homosexual. The
University of Illinois at Chicago and the NIH scientists
report having looked at the genes of 456 men, each of whom
had at least two gay brothers, from 146 families. The
finding that a variety of genes are common to most gay
men echoes other recent gene research.
Charlie Kirk DID say stoning gay people was the 'perfect law' — and these other heinous quotes