We may not even need scientists deliberately changing human genetics. Feed people enough chemicals and something in the genetics changes.
In Brazil there is an outbreak of microcephaly -- babies born with unusual tiny heads and brains.
Why?
Well there are differing opinions, but the most plausible is:
"According to the Physicians in Crop-Sprayed Towns (PCST), a chemical larvicide that produces malformations in mosquitoes was injected into Brazil's water supplies in 2014 in order to stop the development of mosquito larvae in drinking water tanks."
"The chemical, which is known as Pyriproxyfen, was used in a massive government-run program tasked to control the mosquito population in the country."
"Malformations detected in thousands of children from pregnant women living in areas where the Brazilian state added pyriproxyfen to drinking water is not a coincidence," the PCST wrote
pdf in the report."