Dairankou!! Semen Sisters -Mawari Mawatte Wa Sarete-

The year is 20XX, and the Global Youth Decency Treaty is in full effect. Pornographic materials have been banned and there is an overwhelmingly approved strategy to wipe out the underground porn trade in one sweep.
Naturally many of the treaty's supporters are female, as well as cliques of male social sycophants who call themselves men.
However, the effects of the treaty have been extremely adverse. Depression and death are on the rise. Sex education is distorted and utterly rejected. Marriage and birthrates have plummeted.

To help the ailing human race of now, a particular group of scientists create two intercourse androids, SHS-87 and SHS-88, to send back in time. Before it's too late.

[From English DLSite]