sperm's life

My bf had night fall the night before we had sex.. he removed his wet underpants in morning..2 hrs later we had unprotected sex. he stopped midway fearing tht he may hv sperm on his pennis due to night fall. its my 21st dy of 28 dy cycle.
is there any preg risk??

[Kevin Kennedy, Ph.D.]

How long sperm cells can remain viable depends on the environment in which the cells are living. Outside the body sperm survive only a few minutes to a few hours. Inside the vagina they can survive for five days or longer. So, as you can see, there is no single answer, but it is very unlikely but possible that pregnancy could occur.