You're contradicting yourself.  Is it a choice, or not?  Are you saying homosexuals have a choice, but heterosexuals do not?  Doesn't that imply that, given a choice, 100% of people choose to become homosexual?  Does that make sense?  I think not. 
  
Regarding your "99.999%" figure -- I take it you interviewed 100,000 gay people and 99,999 of them told you they made a conscious choice to become gay?  Riiiiight.  In fact, have you ever talked to a single gay person who told you this?