Every virus on earth has one goal. To spread and multiply. As long as humans have lived disease has been one of are greatest enemies. That was until the outbreak of a new virus believed to have originated somewhere deep in the south American rain forest. The effects were so subtle that no one noticed at first. It presented similar symptoms to the common cold after infection till it learned to adapt to its new host. It went to work attacking any other viruses in its new host. That was when doctors began to notice though they didn't know why at the time. Afterwards it attacked the body in ways a virus never had before. Most viruses would kill the host but this one wanted the opposite. It was the apex of viruses and it had found its apex host. It wanted new host to infect and thus it attacked the human reproductive system. Women no longer experienced monthly menstrual cycles. Every month the body would release a new egg and it would permanently attach itself to the womb. Unprotected sex had an almost one hundred percent chance of impregnation. But they were not alone. Men experienced no refractory period being able to maintain an erection as long as they were sexually excited. They were able to have intercourse multiple times or with multiple partners. The sex drive likewise was heightened in both sexes. It however didn't come without a price. The virus mutated and adapted to its host meaning each person carried a new strain of the virus after a few years. When it came to men the virus would attack another male with a different strain of the virus if they came into contact. When a man had sex with a woman some of the virus was transferred and if it detected the virus of another it would attack it to ensure that strain was passed onto any offspring. Meaning multiple men having sex with the same woman or each other could mean death. The world changed after the virus and me, I have to live in it.
Realy complicated idea, I realy don't see way how to put this in atractive story. But concept of new virus is still realy intresting, I curios if you write something.
I like it. This is a much more complex story idea than just sex. There is a bunch of interesting ways this could go.