As a veterinary student who just took an exam in parasitology I feel the need to reply. One of the things that most people don't know is that the majority of toxo cases in humans are not due to exposure to cat feces, but from eating undercooked meat, particularly mutton, venison, and pork and from drinking unpasteurized goat milk. There are many more human cases of toxo in Europe due to this reason. As mentioned before, the parasite is the biggest risk for pregnant females due to risk of abortion, and those who are not pregnant may or may not show symptoms (it is suspected that as much as 20% of the population has an antibody titer to toxo). The good news it that a cat is only infective while it is shedding oocysts which is about 1-3 weeks, and once it has stopped shedding it is protected for life. This means that as long as you practice good hygiene with the litter box (change every day, wash hands after cleaning) there is almost no risk of contraction. If it is really a problem you can have the cats titers checked and if they are positive there is absolutely no risk of infection, even to pregnant women, or just get an older cat who has a high likelyhood of already being exposed.