Amethyst's Favorite

So I once came here totally out of boredom and this manga stood out, I can’t recall how the image or name of the manga is but I remember the details.
The manga because an asteroid hit earth and radiation began to cover the planet, soon after babies began to be born who were resistant to radiation. The main character isn’t resistant to radiation but the studies hard for what he wants. By the way it’s a shounen-Ai