I didn't read to verify, but here's just some quick links that show up on google regarding the subject. When I have more time I'll dig through and post a more in-depth response.
Sexual Abuse: A Major Cause Of Homosexuality?
Research has shown that traumatic stress, including stress caused by sexual abuse, causes notable changes in brain functioning and development.[61][62] Various studies have suggested that severe child sexual abuse may have a deleterious effect on brain development. Ito et al. (1998) found "reversed hemispheric asymmetry and greater left hemisphere coherence in abused subjects;"[63] Teicher et al. (1993) found that an increased likelihood of "ictal temporal lobe epilepsy-like symptoms" in abused subjects;[64] Anderson et al. (2002) recorded abnormal transverse relaxation time in the cerebellar vermis of adults sexually abused in childhood;[65] Teicher et al. (1993) found that child sexual abuse was associated with a reduced corpus callosum area; various studies have found an association of reduced volume of the left hippocampus with child sexual abuse;[66] and Ito et al. (1993) found increased electrophysiological abnormalities in sexually abused children.[67]
Some studies indicate that sexual or physical abuse in children can lead to the overexcitation of an undeveloped limbic system.[66] Teicher et al. (1993)[64] used the "Limbic System Checklist-33" to measure ictal temporal lobe epilepsy-like symptoms in 253 adults. Reports of child sexual abuse were associated with a 49% increase to LSCL-33 scores, 11% higher than the associated increase of self-reported physical abuse. Reports of both physical and sexual abuse were associated with a 113% increase. Male and female victims were similarly affected.[64][68]
Navalta et al. (2006) found that the self-reported math Scholastic Aptitude Test scores of their sample of women with a history of repeated child sexual abuse were significantly lower than the self-reported math SAT scores of their non-abused sample. Because the abused subjects verbal SAT scores were high, they hypothesized that the low math SAT scores could "stem from a defect in hemispheric integration." They also found a strong association between short term memory impairments for all categories tested (verbal, visual, and global) and the duration of the abuse.[69]
Child sexual abuse - Wikipedia, the free encyclopedia
William C. Holmes, MD, MSCE, Assistant Professor of Medicine and Epidemiology at the University of Pennsylvania School of Medicine, and Gail B. Slap, MD, Associate Chair of Pediatrics at the University of Pennsylvania School of Medicine, in their Dec. 2, 1998 Journal of the American Medical Association article "Sexual Abuse of Boys," stated:
"Sexual abuse of boys appears to be common, underreported, underrecognized, and undertreated...
Abused [male] adolescents, particularly those victimized by males, were up to 7 times more likely to self-identify as gay or bisexual than peers who had not been abused. No longitudinal studies examined the causal relationship between abuse and gender role or sexual orientation, however. Gender role nonconformity and gay or bisexual identity may precede abuse."
Can childhood sexual abuse by a person of the same sex cause homosexuality? - Born Gay - ProCon.org
As you can see from these articles, people are on both sides here, so all in all, I can say it's inconclusive, to a point. I do however lean towards the part of a possible cause, as sexual trama does cause brain damage in studies, which may or may not include homosexuality.
And yes, the meaning of life is reproduction. That's it. The yearning for more is just something we as humans need(hence the creation of religions in general), as we fear death, and don't want to believe death is really the end. I mean, if this wasn't the case, do ants, dogs, cats, lions, tigers, and bears (oh my!) all ponder the meaning of their lives? Human emotions are confusing, and downright illogical. One you factor them out of the equation, the answer is really simple, really.
So is there anything conclusive to support my argument? No. Absolutely not. It's a theory, and an evolving one at that. But it is based purely on logic, and I invite anyone to try and find flaw in my argument. Any kind of emotional response is pretty much invalidated, because emotions which drive us, and make us human, also blind us to the obvious truths out there.
All that being said, please note I personally don't have any hate, dislike, or hold anything against homosexuals. I don't hold things against other people who are different, being if they are a different color, sexual preference, ethnicity, or handicapped, it is not something they choose for themselves, and it is just who they are. And we all need to try harder to push acceptance and not just mere tolerance. Despite my beliefs on the causes of homosexuality, the meaning of life, etc, you should see me as an ally and not a foe, as my arguments are once again, based on logical thinking without the barriers of emotion to get in my process of thinking.
Ask Hitler. 
