A Canadian study grasps at straws
in the latest attempt to "prove" that homosexuality is innate:
Professor Anthony Bogaert from Brock University in Ontario, Canada, studied 944 heterosexual and homosexual men with either "biological" brothers, in this case those who share the same mother, or "non-biological" brothers, that is, adopted, step or half siblings.
He found the link between the number of older brothers and homosexuality only existed when the siblings shared the same mother.
The amount of time the individual spent being raised with older brothers did not affect their sexual orientation.
Clayton Cramer addresses some problems with the methodology, in addition to some of Bogaert's past research.
Researchers such as Bogaert seem unwilling to address the fact that each of the twin studies has found sets of identical twins who have the same genes and the same prenatal physical environment but different sexual orientations.
Update: Clayton Cramer has more on twin studies. He mentions the 1952 Kallman study that found a 100% concordance rate among monozygotic (identical) twins. That and other twin studies are cited here. Kallman involved 85 sets of twins, 45 fraternal and 40 identical. Of the latter, the sexual orientations of three cotwins were unknown and were not counted in the study. But was this a representative sample?
The exact method of recruitment is unclear from the report, but it is stated that "the search for potential index cases was organized not only with the aid of psychiatric, correctional, and charitable agencies, but also through direct contacts with the clandestine homosexual world."
Given the mores of the time, one wonders if getting a representative sample to participate in a sex survey was even possible in the 1950s - much less 1947, when Kinsey published the first of his reports.
No other twin study reports a 100% concordance rate, unless you count individual case studies.
The twin studies show that some homosexuality could be biological in origin, and that some is definitely not. The activist community cannot tolerate such heresy; its fellow travelers in the research community looks only for a biological explanation.