Plethysmographic testing. They can't lie on that one.
'Course they'll just scream discrimination (of course it is) and get any test banned, just like they did back in 1981, when they got so ugly about how the straight community was killing them by refusing to drop a mint on medical research for their malady..... which they were telling us at the same time was everyone's problem ..... which was going on at the same time they were suppressing claims by forensic health workers down in the Rio Grande Valley who thought certain AIDS cases among ag workers had to have been propagated by mosquitoes. That claim was instantly suppressed on grounds it "might start a panic" ..... showing that the 2% minority were already busily at work modulating concern levels among the bovine crowd of straights, to get the right political response. Like milking a cow.
How does it work?