Ok, so let's say you have
Carleyand Megyn in the room auditioning for a show, Carley is dresses like the photos and I believe was 22 when she started with Fox, while Megyn first applied for Fox news when she was 34.
You could go the age route and say you're looking for someone under 25 years old.
Or if you wanted to be more crafty, you can say that Carley has a journalism degree while Megyn went to law school, and you want someone with a journalism background because it's a news show.
The real reason could very well be that Carley's perky tits would be more attractive to your viewers (and you & the other "judges" in the room). But that doesn't matter, all you need is a plausible explanation that doesn't infringe on human rights.
Boom. Done.