genetical engineering to prevent overpopulation has been done before (2001)

It can be hard to believe that people would purposely try to make a product designed to make people infertile. 

But it's been done before: 

https://amp.theguardian.com/science/2001/sep/09/gm.food?__twitter_impression=true

Scientists have created the ultimate GM crop: contraceptive corn. Waiving fields of maize may one day save the world from overpopulation.

The pregnancy prevention plants are the handiwork of the San Diego biotechnology company Epicyte, where researchers have discovered a rare class of human antibodies that attack sperm.

By isolating the genes that regulate the manufacture of these antibodies, and by putting them in corn plants, the company has created tiny horticultural factories that make contraceptives.

Contraceptive corn is based on research on the rare condition, immune infertility, in which a woman makes antibodies that attack sperm.

'Essentially, the antibodies are attracted to surface receptors on the sperm,' said Hein. 'They latch on and make each sperm so heavy it cannot move forward. It just shakes about as if it was doing the lambada.'