Biosocial data

Question 1

Handedness and homosexuality

Answer 1

Homosexual men have an 82% higher chance of being non-right-handed than heterosexual men (Lippa, 2002). Presumably does not apply to women.

Question 2

Fraternal birth order effect on sexuality.

Answer 2

Each older brother increases a male’s odds of being homosexual by 28-48%. Identified by Ray Blanchard. Also seen in male-to-female transsexuals.

Question 3

Handedness statistics.

Answer 3

Left-handedness - around 10% worldwide. Mixed-handedness - ?

Question 4

Sexual orientation

Answer 4

Men - 2-4% homosexual, 1-3% bisexual;

Women - 1-2% homosexual, 2-5% bisexual

(US 2006-2008; National Health Stat Report, March, 2011)

Question 5

Handedness by gender

Answer 5

Approx. 13% in males and 11% in females, or around a 2% more or less consistent difference.

(Gilbert & Wysocki, 1992; Peters, Reimers, & Manning, 2006)

Question 6

Handedness heritability

Answer 6

With two left-handed parents - ca. 26%

With one left-handed parent - ca. 20%

(McManus & Bryden, 1992)