Scientists in Oregon have produced four monkeys using the genetic material of two females, a breakthrough that could lead to the same technique being performed in humans.

Researchers from the Oregon Health & Science University replaced most of the genes of one rhesus macaque monkey with genes from another, according to The Washington Post. They then implanted embryos (fertilized with sperm), into the uterus of another monkey, who gave birth to four healthy offspring.

The experiment is a step toward helping humans prevent genetic deformities in their offspring. Defects in mitochondrial DNA can produce disorders including seizures, diabetes, and Alzheimer's, Parkinson's, and Huntington's diseases.

However, the procedure may also raise ethical and societal concerns. This method incorporates three genetic parents, leading to possible legal hassles. Also, according to the article, the procedure could tamper with the "germline," permanently altering genes for future generations.

"We realize this is not just a simple form of gene therapy," said lead scientist Shoukhrat Mitalipov. "This type of gene therapy involves replacing genes in the germline which of course will be transmitted to next generations, which is a concern. However, we're talking about patients and birth defects that cause terrible diseases due to these gene mutations. So the only way to prevent these birth defects is to replace these genes."

The full results will be published in the journal Nature.