Can dry humping cause pregnancy by precum,while girl wear underwear and sanitary napkin,boy has underwear too?because answers in site are different.

Never a good idea: Although it is unlikely that pregnancy could occur, it is NOT imposslble. It is always best to avoid any situation where sperm could possibly get close to the vagina. Precum has a very large quantity of sperm, and they are able to swim up the vagina. It only takes one sperm to cause pregancy. It is safest for pregancy prevention and to prevent STDs to use a condom always, even in this scenario.