Newer contraceptive may target sperm movement to the site of fertilization.
Sperm tails reveal clue to non-hormonal contraceptives for either sex
In humans, CatSper is a channel that ferries calcium ions in and out of sperm. With progesterone, it rapidly inundates sperm with calcium ions. But sperm without CatSper can’t become hyperactive.
Once researchers have located where progesterone binds to the CatSper channel, she adds, they can look for molecules that would block this interaction, rendering sperm sterile.