First, I am sorry that I can't remember the source link about this info (may be in 2010) but here is what it said
There is no 100% str8
63% str8 guys had anal sex with other guy
74% had/give a blowjob from/for other guy
and almost 95% had jerked each other off
All this with "once in their lifetime"
Is it that true? Is it due to the time when they "were" bicurious and then they turned to straight?