We have two Persian fluff balls for cats, and one insists on sleeping in the sink.

According to The Atlantic, the parasite Toxoplasmosis gondii comes into us by undercooked meat, well-intentioned placentas (what?), gardening soil, or, most infamously, cats. It is the reason that pregnant women are not supposed to empty litter boxes.

“If you’re young and healthy and have it already, it might provide some benefit, as we saw in our research,” says Ann-Kathrin Stock, a cognitive neurophysiology researcher at the University of Dresden in Germany. “But the adverse effects are potentially huge. If you ever really get sick it might be what kills you.”

Many people have what feels like a cold after they get infected with Toxo. The symptoms pass, and the person feels fine. But the Toxo lives on inside them, hidden dormant in little cysts, kept in check by constant pressure from the person’s immune system. If our immune systems become weak, because of a serious illness later in life, though, the Toxo can break out and attack organs like the brain or retina.

“You might lose your ability to see, or lose your cognitive faculties,” Stock said.

Neuroscientist Joraslov Flegr, an eminent voice in Toxo research, told The Atlantic last year that, “Toxoplasma might even kill as many people as malaria, or at least a million people a year.”

What does it mean to learn that it can also have beneficial effects?

Toxo has been all over the news in recent years, since it became known that the parasite manipulates people’s behavior. Maybe most interestingly and notoriously, it seems to make men more introverted, suspicious, unattractive to women, and oblivious to the way others see them.

Clearly, I have Toxo.

Infected women, inversely, have been shown to be more outgoing, trusting, sexually adventurous, attractive to men, and image-conscious.

Clearly Amy has Toxo.