The Science of Gay

SCIENCE GAY of Here are a few really cool peer reviewed findings about the genetics of gay folks. Neil Patrick Harris image via Dr. Horrible's Sing-Along Blog HOMOSEXUALITY IS EVERYWHERE AROUND 10% OF THE HUMAN POPULATION IS GAY 3.4% 20% There is no firm consensus, estimates range from 3.4% to 20% of the population is gay. HOMOSEXUAL BEHAVIOR HAS BEEN OBSERVED IN 1,500 ANIMAL SPECIES DUCKS & GEESE MATE FOR LIFE CC BY 3.0 Ltshears CC BY 2.0 Delphine Devos 4-5% of goose and duck couples are gay DWARF CHIMPANZEES LIONS To ensure loyalty, male lions often have sex with each other, strengthening bonds The entire species is bisexual PENGUINS DOLPHINS BISON GIRAFFES Some rights reserved by Brendan Riley CAN HORMONE EXPOSURE BEFORE BIRTH ALSO HELP DETERMINE WHETHER SOMEONE WILL BE BORN GAY? Match the slopes of lines ON AVERAGE, IN REGARDS TO SPATIAL AWARENESS Spatial judgment research suggests early exposure to hormones, such as testosterone, in the womb contributes to this ability • Men were better at matching angles than women • Gay men scored worse than straight men Answer is at the bottom, • Lesbians scored better than straight women THE 'DIGIT RATIO' WAS ASSOCIATED WITH SPATIAL JUDGMENT ABILITY: The shorter your index finger relative to your ring finger, the DIGIT RATIO THE LENGTH OF A PERSON'S FINGERS may indicate their sexual orientation more testosterone exposure. Gay men and Straight women are more likely to have a longer index finger (relative to ring finger) • Lesbians and Straight men are more likely to have a shorter index finger (relative to ring finger) Digit ratio between index and ring finger are thought to be affected by the amount of testosterone exposure in the womb. HIGHER LEVELS OF TESTOSTERONE ARE ASSOCIATED WITH A SHORTER INDEX FINGER RELATIVE TO THE RING FINGER CAN HORMONE EXPOSURE BEFORE BIRTH ALSO HELP DETERMINE WHETHER SOMEONE WILL BE BORN GAY? IN WOMEN, THOSE WITH A MORE MASCULINE DIGIT RATIO ARE MORE LIKELY TO BE GAY Studies have shown both hypermasculine ratios as well as feminine ratios in gay men According to a study by Dennis McFadden, a psychology professor at the University of Texas at Austin HANDEDNESS Gay men are Lesbians are 31% 91% more likely to be left-handed than heterosexual men more likely to be left-handed than heterosexual women HAIR WHORL The gene that controls the direction in Why? which hair grows may be linked to left-handedness and sexual orientation Yes, serlously, it's spelled whorl In one survey, Can you tell if someone's gay BY THE DIRECTION OF THEIR HAIR WHORL? 23% In the general 8% population, only have counterclockwise of gay people had counterclockwise hair whorls hair whorls BIRTH ORDER HAVING OLDER BROTHERS may be a factor in DETERMINING MAY INCREASE THE LIKELIHOOD THAT A MAN WILL BE GAY SEXUAL ORIENTATION Older sisters don't have an effect, and it doesn't matter if the brothers grow up in the same home The odds of a man being gay increases by 15% 33% i1 of gay men CAN ATTRIBUTE HOMOSEXUALITY TO THEIR BIRTH ORDER for every additional older brother that he has according to research by Ray Blanchard and Anthony F. Bogaert of the University of Toronto Let's explain. Epigenetics are Epigenwazzit? inheritable factors that regulate WHY WOULD BIRTH ORDER BE A FACTOR? DNA, switching genes on and off Epigenetic changes After giving birth to sons, the have evolved to benefit mother's body may fight the production of another male by "feminizing" sexual orientation A study published in The ww.Quarterly Review of Biology suggests that epigenetics are the biological driving force behind sexual orientation adults but are some- times passed to their children. Epigenetics may be responsible for the response in mothers of multiple Inherited epigenetic markers may explain why homosexuality seems to sometimes run in families, despite the lack of a "gay gene" confirmation sons. Twin Brothers This study found that gay men share genetic signatures on part of the X-chromosome: Xq28 THIS STUDY FOUND THAT GAY MEN SHARE GENETIC SIGNATURES ON PART OF THE IN A STUDY OF 400 SETS OF TWINS, XQ28 X-CHROMOSOME: RESEARCHERS AT NORTHWESTERN UNIVERSITY HAVE FOUND GENE MARKERS THAT MAY CONTRIBUTE TO SEXUAL ORIENTATION Some rights reserved by rafael-castillo Brain Scans Gay men Lesbians and and Heterosexual Heterosexual women men the two halves of the brain are more or less the same size the right hemisphere of the brain is slightly larger "This is yet another in a long series of observations showing there's a BIOLOGICAL REASON FOR SEXUAL ORIENTATION" Dean Hamer, a molecular biologist at the National Institutes of Health (NIH) WHEN DID THEY DECIDE TO BE GAY? WHILE THERE HAVE BEEN NO STUDIES TO CONCLUSIVELY SAY WHAT DETERMINES SEXUAL ORIENTATION, it is widely accepted in the scientific community that genetic and developmental factors both play a role. WHEN DID YOU DECIDE TO BE STRAIGHT? Exactly. Genetics had a role to play. And frankly, it's none of your business anyways. SOURCES: presented by: BestMedicalDegrees.com Birth Order: http://bit.ly/sci-of-gay-birthorder Fingers: http://bit.ly/sci-of-gay-fingers2 Twin Brothers: http://bit.ly/sci-of-gay-twins Birth Order: http://bit.ly/sci-of-gay-birthorder2 Gay Animals: http://bit.ly/sci-of-gay-animals Hair Whorl: http://bit.ly/sci-of-gay-hair XQ28: http://bit.ly/sci-of-gay-xq28 Digit Ratio: http://bit.ly/sci-of-gay-digitratio DEVELOPED BY Fingers: http://bit.ly/sci-of-gay-fingers Epigenetics: http://bit.ly/sci-of-gay-epigenetics NOWSOURCING