No, this is a great question, and a commonly believed myth, too! The idea here is that if a guy were to ejaculate onto a toilet seat, and then a girl sat there, she could get pregnant. This is not true for a few reasons… For one thing, it is pretty rare that somebody would ejaculate on a toilet seat in the first place! But even if a guy did, sperm cannot live very long outside the body. They prefer warm environments and don’t like to be exposed to air, so they especially don’t have a very good chance of surviving on a hard, cold toilet seat!
There would be a very small chance of pregnancy happening if a vulva and/or vagina or vaginal fluids came into direct contact with the ejaculate on a toilet seat, but only if they sat there right after a guy ejaculated onto it. Plus, when a female body sits on a toilet seat, her vulva/vagina usually does not touch with the seat so this situation is really not that likely.