Not really Barry, it's just as rare in nature as it is in us.
Looking at this objectively, There is no evolutionary advantage to homosexuality which is why it's not natural in a biological sense.
If it was natural and common then we would not have the diversity of life as we do.
So to propogate a species, we need a nut and a bolt, two nuts can't do it.
As far as wanting gay marriage goes, what these guys don't understand is that marriage between a man and woman is probably the most sacred institution we have, so for a very small minority to expect the majority to turn that on it's head is a big ask, so you can't blame or criticise people for not accepting it.