Currently, women who seek emergency contraception within 72 hours of intercourse can receive copper intrauterine devices. Though the devices are very effective at preventing pregnancy, they must be administered by a highly trained clinician and are not universally accepted by patients, as they have a higher risk of complications than oral applications. These factors stand as deterrents to some women obtaining emergency contraception after a 3-day period.
Prevention is better than cure Sam. Get a vasectomy.
I think I had it as a kid, though.