Female sweat different PH from men?

Just watching Bones, and from analysing the sweat on a piece of evidence, and finding the PH is 7, they all realise it’s a woman, in an “Oh, of course” way.

Is this true?
Why is this?

I had always heard that guy sweat was more acidic than girl sweat. However, these guys disagree (2001):

Erroneous gender differences in axillary skin surface/sweat pH

[sup]*[/sup] That’s the armpit.