I think mixed race women objectively ARE more attractive as an average. The very most attractive women of all races seem pretty equal to me, but if you were going to pick someone by throwing a dart into a crowd of prospective mates (not something I recommend by-the-way) and physical appearance was your number one criterion, I'd pick a mixed-race crowd to throw into. I'm not convinced it applies to mixed-race men, but I'm infinitely less interested.