Dwight Schrute

One ejaculation contains enough sperm to repopulate about 10% of the world's current population.

If I were you, I'd try to make your argument work by focusing on the eggs rather the sperm.

Right, that would work if 100% of the sperm was usable. Not every ejaculation provide a single spermatozoid strong enought to break into the egg shell, and more than one is a rare occurance. Add up the egg shortage you just mentioned, and things gets even worst.

You're a bit behind on your technology: these days, we can just inject the DNA straight into the egg with a syringe. One gay man would therefore provide enough material to repopulate the entire Earth in about the space of an afternoon.

There's much more to it than that, of course, but that's certainly not the bottleneck of the situation by any means.

so stop swallowing it all