How many hours live sperm on outside (on bed or on dress or surface of earth). Because of I sex with my wife on bed. After sex my sister and my mother sleeping at same bed. So many times I clean my semen with my towel nd same towel use my sister (20 years) on bath and wear it with in 1 hour. I dn't know about it. I see today. So I am very worried about it. Tell me doctor if any problem I face with my sister. I am very tensioned.