Sorry, badly worded title, and please, this is a general question I've always wondered - not any kind of veiled homophobia.
It just seems to me that there are more gay MPs as a % of the total compared to the average % in the population?
I just wondered why, really? I find myself thinking that the role is so unconducive to life with family/children maybe that it's only people with fewer commitments who can cope with it?
Or is it a public school bias? 
Or is it not greater than average, but just seems like it because of the media obsession with these things?