Medical funfact #249

We use protamine sulfate to reverse the effects of the blood thinner heparin. One potential side effect exists for males who have undergone vasectomy...

Protamine is made from salmon sperm. Usually, the (human) testicles reside across a special barrier from the rest of the body, much like the brain. If this barrier was damaged during a vasectomy, some of the protamine could cross it. The human immune system would then mount an allergic reaction to the non-human sperm proteins.

And for the beauty pageant contestants out there: no, protamine cannot get you pregnant.