One day I masturbated in the bathroom but during ejaculation very small amount of sperm fall on my sister's underwear which was kept in the bathroom then after this act I washed my sister's underwear 5 times by the help of soap, detergent and liquid dettol then spread her underwear outside on a wire for drying after some times her underwear gets fully dry and the next day she wear the same underwear after it gets fully dry after washing with soap, detergent and liquid dettol. Can she get pregnant by this act?? Please help doctor?