what happens where sperm reaches air? say if its smeared over your hand in really thin layers and barely damp. would it die relativley quickly and/or lose lots of motility?
Sperm and oxygen, COMPATIBLE?
The Wikipedia article on spermatozoon says "The sperm also dies when it hits the air", but there's no citation, and it seems strange to me. They are animal cells and take in oxygen and produce carbon dioxide.
I've had a look in the primary literature, and in [this paper] they find that "Normoxia (air atmosphere) conditions were superior to both hyperoxia (pure oxygen) and no gaseous atmosphere for chilled storage" of Atlantic halibut semen.
Be careful on this. Pure sperm cells probably die when exposed to the air, but cells in semen are not generally exposed to the air even if the semen is.
Example: you and your girl are naked together and involved in sex play but your penis is not in her vagina. The "pre-cum" on the tip of your penis when you are excited but have not ejaculated and the semen that goes everywhere when you do ejaculate contain live sperm cells. If this lands near her vagina or one of you gets it on your hands and then touches her vagina, there is a small chance of pregancy. It does not happen frequently but it does occasionally even when the girl has an intact hymen.
If you look at the link with my name below, and go to the forum on "teen sex" then the topic that is titled something like "Jesus was not the only virgin birth" this will say more about that.