They don't simply just become futanari in a blink of an eye...
no..it takes a trained specialist to sneak in the targets home and inject them with a needle which contains F.u.t.a DNA
After injection the specialist must then fill her targets womb with her own futanari juice.
That is all. The specialist will escape after all procedures are finished, the target will be left unconscious, She will no longer be normal-she will be
FUTANARI
-Birdway