Ok, so I came across a finding the other day, (or year...) that I recently thought about. (It was amazing.)

People have found that molecules mimicking estrogen/androgen compounds have had large biological impacts on many animals. The effect of these compounds has been that some animals have become transgendered, or their behavior altered. This was actually a big issue in the feminization of male fish and frogs. (Although it's odd that absolutely nothing is done about masculization of female species. Look up Tributyltin.)

Now the key point I wish to make is that the effects do not instantly go to these extreme cases where sex is changed. Studies conducted on birds have revealed that steroidal-like compounds have influenced breeding and nesting habits. Males can act as females and vise versa, which has lead to plummeting population size even though all the animals are healthy and capable of reproducing.
Which brings me to my hypothesis: Steroid-like compounds created by industry has given rise to the increase in gay people.

Studies have already linked many of the compounds used today with increases in cancer (approaching 1 in 2 people nowadays) or obesity (look up tributyltin again.) among other things plaguing society nowadays that were almost nonexistent before.

It's simply a toxicological outcome already seen in other species, applied on humans. I'm pretty sure an investigation would confirm at least some portion of the gay community would be straight if it weren't for steroid mimicking compounds.

I am not making any judgment on the morality of being gay or gay people, so please leave that out of this.

Except I do not really see homosexuals using large amounts of steroids

I think a better hypothesis is find that a large amount of body builders are homosexual which I do not see likely.

Please note that chemicals play different roles in different classes (frogs fish and birds are not mammals so your not really making a strong case)

There are indirect methods in getting exposed to such chemicals. And usually, these kind of chemicals do not require a very large dose to have an effect on animals.
Also, you should have really read the wikipedia article. It is toxic to humans. And there's no telling what other side effects it has in store for us.

I did read the wiki it pretty much has no strength in this topic.

For humans: "Tributyltin has also been linked to obesity in humans, as it triggers genes that cause the growth of fat cells." This is physical change not behavioral.

"TBT causes dog whelks to suffer from imposex: females develop male sexual characteristics such as a penis." Dog whelks are not mammals and they are only exhibiting a physical change due to exposure, not a behavioral one.

this has already been theorized. Look up Phthalates.

Phthalates have an Epigenetic effect on children developing in the womb. More noticeably in males. The effects of Phthalates shrink the taint (shortened anogenital distance, no joke) and speed up genital development. Developmentally making young boys similar to girls (in the sense of speed, and the stages of development). [1]

"For example, the phthalates dibutyl phthalate (DBP) and diethylhexyl phthalate (DEHP) produced dramatic changes in male sexual characteristics when exposure took place in utero, at levels far beneath those of previous toxicological concern. These changes included increases in the rates of hypospadias and other indications of demasculinization." [2]

"Researchers found women exposed to higher levels of DEHP and DBP during their pregnancies had preschool aged sons who were less likely to play with "male typical" toys and games. Those "male typical" toys and games include trucks and play fighting." [3]

DEHP and DBP both being common phthalates.

Thank you Prototank. Now my question is whether a study has followed such children into adulthood and determined if their sexual preferences and partners are significantly different from average. (I haven't found any.)

This was not what I was saying, birds aren't steroid users either.
Also body builders that use steroids use ones that are designed to be effective at enhancing muscle, not feminization.

Tributyltin has little to no relevance in this topic, but is a compound which has been shown to have rather negative effects in some populations, but regulations allow it. I realized that the Wikipedia article doesn't do it justice. It is used as a paint on the bottom of a ships hull, to stop growth of living things. Unfortunately it sheds little by little, and this small amount can cause imposex (masculinization) in mollusks, causing their population numbers to drop drastically. It has been banned for commercial vessels, but navy ships are permitted to use it, and were the main culprits of contamination to begin with. So the problem has since been ignored, although it is still quite damaging to populations.
My point in using it was that a big issue in one case can be completely ignored in another case with just as much importance, and that our political system (which is still mainly men) seems to find males becoming females much more of a problem than females becoming males.

Almost all the homos I know, and I think that there is a stat somewhere as well, say that they have been attracted to the opposite sex for as long as they can remember. Which leads me to believe that its genetic.