Featured Research

from universities, journals, and other organizations

University Of Toronto Study Analyzes Chances Of Homosexuality

Date:
May 28, 2002
Source:
University Of Toronto
Summary:
Roughly one in seven gay men may owe his sexual orientation to the fact he has older brothers, say University of Toronto researchers.

Roughly one in seven gay men may owe his sexual orientation to the fact he has older brothers, say University of Toronto researchers.

Earlier studies have shown that each additional older brother increases the odds of homosexuality in a younger brother. "This phenomenon, known as the fraternal birth order effect, was first shown by Professor Ray Blanchard [of U of T's Department of Psychiatry and the Centre for Addiction and Mental Health] and has since been confirmed by other scientists," says CAMH post-doctoral fellow James Cantor. Cantor is co-author of a new study to determine the proportion of gay men whose sexual orientation is due to this effect. "This latest study demonstrates just how important that link is," says Cantor.

In their study, Cantor and colleagues from U of T and CAMH applied statistical analysis to data collected from a sample of 302 gay men and 302 heterosexual men about the number of siblings each had. According to the researchers, the sexual orientation of about 15 per cent of gay men in the sample could be attributed to the older brother effect. Their analysis also suggests that, in the theoretical case of a boy with two-and-a-half older brothers, he would be twice as likely to be gay as a boy with no older brothers.

The study does not determine a cause of the correlation between homosexuality and having older brothers. However, there is growing evidence in other research that it may be pre-natal in nature, based on findings that gay men with older brothers tend to weigh less at birth than straight men with older brothers.

Published in the February 2002 issue of the journal Archives of Sexual Behavior, the study was funded by the Social Sciences and Humanities Research Council, the Centre for Addiction and Mental Health Foundation and the Ministry of Health.


Story Source:

The above story is based on materials provided by University Of Toronto. Note: Materials may be edited for content and length.


Cite This Page:

University Of Toronto. "University Of Toronto Study Analyzes Chances Of Homosexuality." ScienceDaily. ScienceDaily, 28 May 2002. <www.sciencedaily.com/releases/2002/05/020528074252.htm>.
University Of Toronto. (2002, May 28). University Of Toronto Study Analyzes Chances Of Homosexuality. ScienceDaily. Retrieved July 22, 2014 from www.sciencedaily.com/releases/2002/05/020528074252.htm
University Of Toronto. "University Of Toronto Study Analyzes Chances Of Homosexuality." ScienceDaily. www.sciencedaily.com/releases/2002/05/020528074252.htm (accessed July 22, 2014).

Share This




More Mind & Brain News

Tuesday, July 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Do Obese Women Have 'Food Learning Impairment'?

Do Obese Women Have 'Food Learning Impairment'?

Newsy (July 18, 2014) Yale researchers tested 135 men and women, and it was only obese women who were deemed to have "impaired associative learning." Video provided by Newsy
Powered by NewsLook.com
Does Mixing Alcohol and Energy Drinks Boost Urge To Drink?

Does Mixing Alcohol and Energy Drinks Boost Urge To Drink?

Newsy (July 18, 2014) A new study suggests that mixing alcohol with energy drinks makes you want to keep the party going. Video provided by Newsy
Powered by NewsLook.com
Pot Cooking Class Teaches Responsible Eating

Pot Cooking Class Teaches Responsible Eating

AP (July 18, 2014) Following the nationwide trend of eased restrictions on marijuana use, pot edibles are growing in popularity. One Boston-area cooking class is teaching people how to eat pot responsibly. (July 18) Video provided by AP
Powered by NewsLook.com
Understanding D.C.'s New Pot Laws

Understanding D.C.'s New Pot Laws

Newsy (July 17, 2014) Washington D.C.'s new laws decriminalizing small amount of marijuana went into effect Thursday. Here's how they work. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins