You cannot choose your urges, but can choose your actions.
That people might be born with an urge toward the same sex can be argued or not, but to choose to live that lifestyle is still a choice...
That being stated.
The whole natural, unnatural argument is simply odd to me...
We often do things that are unnatural. It is unnatural to speed down a road paved unnaturally with dead dinosaurs pumped from the ground in cars run by the same at speeds exceeding 50 MPH in a vehicle made entirely from human hands manufactured by unnatural processes including smelting, which is also unnatural. It is unnatural to fly in an airplane, or a hot air balloon, to use machinery to go into space, to wear clothes, to manufacture sneakers, to play dodgeball with an artificially manufactured toy, to be able to buy processed food at a grocery store. It is unnatural to do most of the things we do, but that does not mean it should be illegal or that it is a sin. Saying it is unnatural simply isn't enough of an argument to convince me that it is wrong at its core because of the unnaturalness of the act.
Even showing the dangers still doesn't convince me of that, there are plenty of even more dangerous things that people do that are not, nor should they be, illegal. In my state, people regularly ride their motorcycles without a helmet, this is more dangerous than homosexuality to them, it is unnatural, should we make it illegal and label it wrong because of that? People jump out of airplanes, climb rocks, ski, more people die because of the unnatural act of driving every year than die from direct homosexual acts. Since it is more dangerous to drive should we make it illegal?
In other words, that it is unnatural, or intrinsically dangerous is not reason enough for the government to intervene. That it is against a person's religion is still not reason enough to intervene as the government shouldn't be displaying a proclivity towards nor regulating the lives of citizen's according to the dogma of any specific religion. So long as they are consenting adults, I can see no reason that they shouldn't be able to do what they wish with their bodies.