Due to a deadly virus in 2020s, 99.996% of male are killed with minimum female casualty. Afterward, most new birth are female, only 1 out of every 20000 birth are male. Medical science stagnated and never recovered enough to resolve this crisis.
100 years later, society become stable again.
You are fortunate enough to be born as a male in 2120s. You have been treated like a king throughout your life, and at age of 18, you are assigned to a local university as the master and breeder. You are viewed as a hero and celebrity for help repopulating the world.
All girls in the university are 18 years old or older. You have absolute power over them and breed them as you wish. Some strong headed students might hate you for been used like this but there is nothing they can do, you are their master, and have every right over them.
A beautiful lady in her 30s walk toward you: โmy name is Amaya, master. iโm the headmaster of this university. Maybe I can bring you a few girls for you to breed?"