Heads up I'm not familiar with these kind of sites. But to quote the Adultfriender hack article of last month:
Among the 26,939 users with a UK email address, for example, there are just 1,596 who identified as female: a ratio of one woman to every 16 men.[1]
[1] http://www.channel4.com/news/adult-friendfinder-dating-hack-...