Uh-Oh, Scientists Used Human Genes to Make Monkey Brains Bigger

“The scientists call these human-monkey hybrids ‘transgenic non-human primates,’…. the researchers limited their study to monkey fetuses, which were taken out by C-section after growing for 100 days. Allowing the experiment to go past the fetal phase and let the human gene-carrying monkeys to be born would be irresponsible and unethical, study coauthor Wieland Huttner said” - Popular Mechanics