Scientists are going to foreign countries to develop chimeras, which is a combination of animal and human.
In one case, Spanish and Americans scientists are in China to fuse human cells into the embryos of monkeys to "make progress for the sake of people who have a disease," says one scientist from Murcia Catholic University in Spain.
Dr. Tara Sander Lee of the Charlotte Lozier Institute warns that the human cells could end up anywhere in the animal.
"These early human cells – which could, in theory, give rise to every cell and tissue in the human body – could in the worst-case scenario go to the gonadal tissue and form human sperm and eggs in the monkey's body," she explains. "And there we have a serious issue and worry about the breeding of these animals that could be part human."
According to Lee, the cells compete with each other – so the result could be a wide range of chimeras, more human than monkey or vice versa.
"You could also have development of an animal that has a partially or fully human brain," she tells OneNewsNow. "So part of the animal could be monkey … but some significant parts of the animal could be directed by and under the control of a human brain."
Scientists in Japan are doing the same to humanize mice.
Observers argue that the reason scientists are going to other countries is it's considered unethical science in the U.S. and many others – and Lee says it should be abandoned.