i was wondering, how quickly do sperm die? if they are exposed to air such as if they're on clothes or the fingers, will the sperm still be able to impregnate the woman if the sperm on the clothes or fingers gets onto the vagina? i know it's unlikely sperm can go through layers of the clothing, but will the woman be in danger if the sperm gets on the underwear right near her vagina or the man's fingers sweep over the vagina?
No matter where sperm is it can get you pregnant... Air doesnt do anything for it. it still stays there. If sperm is introduced anywhere near the vagina you can get her pregnant. So my advice would be either wash your hands after you get stuff on them or wear a condom from the get go. Sperm dies anywhere between 2-4or5 days after it is introduced outside of the body.
You need at least 5 million sperm deposited at the cervic entrance to have a hope of causing pregnancy and several hundred at least must find the egg and work together to get one inside. So semen deposited outside the vagina has virtually zero chance of getting that number of sperm inside or to the egg.
"No matter where sperm is it can get you pregnant... Air doesnt do anything for it." is very misleading because both statements are incorrect. Sperm is not magic and cannot travel from one external place to the uterus all by itself. It has to be put within a reasonable distance. Sperm just does not go from the vulva to the cervix without help. (And to really pick at the sentence, if the semen ends up on your feet, this statement says you could pregnant from that too, lol.) And air does kill sperm, it's a simple fact. Not immediately, but air dries sperm, sperm dies when it dries (and when it gets to hot or cold too). Semen that is completely dry does not have living sperm in it.
As for how much is 5 million, I think the average ejaculation has highter than 200 million so it's a very small portion of it. Just make sure your hands are clean and semen stays out of the vagina.
It only takes one sperm to make somebody pregnant. In theory, though the odds are low, a single sperm placed in the vagina (through clothing, by a finger, whatever) could fertilize an egg....so don't take any chances if you don't want that to happen.
At normal temperatures in a dry environment, I would be surprised if sperm lived anymore than 48 hours outside the body. however, add moisture to the environment (like actually being in a female) andit could stay alive for at least 3 days, probably more. If you are in a hot tub, sperm will die much, much faster. Sperm don't like high temperatures.