Information from wikipedia, for I am just doing a quick summary

Sexual orientation and suicide
See also: Homosexuality and psychology

The likelihood of suicide attempts are increased in both gay males and lesbians, as well as bisexuals of both sexes when compared to their heterosexual counterparts.[19][20][21] The trend of having a higher incident rate among females is no exception with lesbians or bisexual females and when compared with homosexual males, lesbians are more likely to attempt than gay or bisexual males.[22]

Studies vary with just how increased the risk is compared to heterosexuals with a low of 0.8-1.1 times more likely for females[23] and 1.5-2.5 times more likely for males.[24][25] The highs reach 4.6 more likely in females[26] and 14.6 more likely in males.[27]

Race and age play a factor in the increased risk. The highest ratios for males are attributed to caucasians when they are in their youthhood. By the age of 25, their risk is down to less than half of what it was however black gay males risk steadily increases to 8.6 times more likely. Through a lifetime the risks are 5.7 for white and 12.8 for black gay and bisexual males. Lesbian and bisexual females have opposite effects with less attempts in youthhood when compared to heterosexual females. Through a lifetime the likelihood to attempt nearly triple the youth 1.1 ratio for caucasion females, however for black females the rate is affected very little (less than 0.1 to 0.3 difference) with heterosexual black females having a slightly higher risk throughout most of the age-based study.[27]

Gay and lesbian youth who attempt suicide are disproportionately subject to anti-gay attitudes, and have weaker skills for coping with discrimination, isolation, and loneliness,[27][2 and were more likely to experience family rejection[29] than those who do not attempt suicide. Another study found that gay and bisexual youth who attempted suicide had more feminine gender roles,[30] adopted an LGB identity at a young age and were more likely than peers to report sexual abuse, drug abuse, and arrests for misconduct.[30]

One study found that same-sex sexual behavior, but not homosexual attraction or homosexual identity, was significantly predictive of suicide among Norwegian adolescents.[31] In Denmark, the age-adjusted suicide mortality risk for men in registered domestic partnerships was nearly eight times greater than for men with positive histories of heterosexual marriage and nearly twice as high for men who had never married.[32]

http://en.wikipedia.org/wiki/Epidemiology_of_suicide