It helps from a probabilistic point of view, but with about 10% of the population identifying as either homosexual or bisexual, it doesn't really remove the problem, just makes it less common.

makes it less common to where it's not really a problem.

Like how stores go into buisness knowing there will be stealing, but if there is too much it's not worth it.

Slightly bad analogy

Theft from stores you are giving up money (hiring security guards etc) to gain money. Obviously, you will take such actions where the cost to do them is less than the benefit gained, and in each case it's fairly easy to objectively describe the cost/benefit.

With this, we are giving up the abstracts of dignity and privacy  to gain the abstract of security. The relative importance of these is completely subjective. There is no objective way to say, yes, seperation by gender is the point at which any extra improvements to privacy are too expensive in terms of security.

Additionally, these machines do not work. As I said in my first post.

http://prof77.wordpress.com/2010/04/24/full-body-scanners-useless-air-security-expert-says/

http://boingboing.net/2010/01/22/naked-airport-scanne.html

I know, right? Its almost like airplanes are the only way al queda has attacked the us. 

http://en.wikipedia.org/wiki/1993_World_Trade_Center_bombing

@Others
My apologies for not responding to you. Some raise valid points, others make me sigh and wonder why I bother discussing anything not game related on this forum. Unfortunately I have neither the energy nor the will to engage either side due to an absolutely horrific turn of events in my personal life. The above was a quick and easy search that also happens to support my general stance.

With a death toll of 6 vs over 3000 for air attack. 

1000 injured, and untold economic damage to match. And, surprisingly, the exact same target and intentions. Maybe they were more fixated on making a statement than a means of inflicting the damage. Absurd thought I know.