Castration will stop your hair loss, but I wouldn't recommend that! Just get a hair transplant if you are that vain. It is not normal to have an enlarged prostate after sex - this only happens if you are delaying ejaculation too long and overstimulating it - or building up too much sexual energy that doesn't get completely released. It is important for the pelvic region to move to release energy - masturbation with the hand only can cause sexual energy to stagnate. Hair loss is genetic and passed down from the female side of the family.