How Ponies Reproduce

I've always gone with the theory that ponies have genitals in their stomachs, explaining why they have no genitals that we can see. Female ponies have sensitive mouths and a stomach that doubles as a uterus, allowing them to get pregnant and eventually vomit out children.

Male ponies have their penises in their stomachs, so in order for them to get an erection they have to bend forward, allowing their genitals to extend out their mouths. By kissing a female pony, they spread their seed into her throat, getting her pregnant.