What is the probability of conception in situations when sperm
isn't directly ejaculated into the woman's vagina, like: - The
man's or the woman's hands come into contact with sperm, for
example when removing a condom. (Perhaps after washing them,)
the hands later touch vagina, for example during foreplay to
another intercourse. - The man and the woman taking a bath
together, the man ejaculates into the water. - The man
ejaculates on the woman's body, perhaps on or around vagina but
not inside. (In this case it could also make a difference
whether the woman has shaved pubic hair or not.) - The man
ejaculates during receiving oral sex, (perhaps the woman rinses
her mouth), the couple kisses, the man performs oral sex to the
woman. In all these situations, it seems possible that a tiny
amount of sperm is eventually transferred into vagina
indirectly. And since just a single cell is enough to fertilize,
it seems that there is non-zero probability of conceiving. How
much care need to be taken to prevent conceptio