> Do the parasites make their hosts more attractive so they are more likely to be passed on, or do more attractive people have more sex that gives them opportunities to be infected?

T. Gondii reproduces in felines, and is transmitted initially through their feces to other hosts. Humans catch it most often through infected food (meat, vegetables) or liquids (water, milk). Humans cannot transmit T. Gondii to other humans, unless pregnancies, organ transplants or cannibalism are involved.

So, regardless of how attractive an host is, he won't have more or less opportunities to be infected with T. Gondii than anyone else. This is not a STD.

Unless there is some sort of correlation between attractiveness and eating poorly corked meat.