The science of either preventing revolting, dirty or otherwise objectionable people from reproducing.
Alternatively, preventing unwanted reproduction by cock-blocking lovebirds with something disgusting, most appropriately a third person's poor personal hygiene.
The ewgenics program is an advanced form of birth control that involves turning off peoples' showers until they are too smelly to consider getting close enough to make babies.
Ink applied under the skin with a tattoo machine
Tattoo's...That stuff that crazy people, that like pain, get when bored hahaha