18+ Iya na Kao sare nagara Kozukuri sasete Moraitai

The protagonist Akito Kishizaki leaves his hometown located near a mountain where he is pretty much the only young person to look for his ideal woman. When he reaches a metropolis, he is abducted and informed that a virus has been spreading throughout the world and making all men impotent, but Akito has an antibody that neutralizes the virus. After some research, it is discovered that his whole town is immune to this virus, but he is the only man capable of reproducing in that town since the most of the town consists of elderly, so in order to secure the human population he has to make babies with people. But when pictures of him are shown worldwide, no woman comes forward to have sex with him. The first-rank sperm officer Ayumi Himekawa gets designated to make babies with him. But little did she know how much she would regret it...