There has been a report from the Chinese Academy of Sciences, saying that baby mice were made with two moms and no dad. The report states that it required genetic engineering to make it possible and to break nature's rule of reproduction.
The scientists tested with two male mice and two female mice. The females were still healthy and were able to have their own babies. However, the babies from the two males died a few days after they were born.
Why do scientists make tests like this?
The focus of the test is to answer why there's a need for sex. Every mammal (that includes us) can only reproduce through sex. It requires an egg cell and a sperm cell to form a baby.
However, some species in the animal kingdom do not follow that rule. In short, they can reproduce babies without the need for having sex. These include fish, amphibians, reptiles, and birds. They don't need to have sex to reproduce.
The primary goal of the researchers in China was to identify which natural rules of reproduction can be broken to reproduce baby animals from parents of the same sex. This helps them gain more understanding of why the rules of reproduction are important.
How was the test done?
It required a lot of "cutting edge" science. The researchers admitted that it was easier to do with two females than with two males. Here's how they did it.
They took an egg from a mouse and a particular cell from another. That particular cell was a "haploid embryotic stem" cell. Both of the cells contained just half of the required DNA. However, this wasn't enough.
The researchers used gene editing in order to delete three sets of DNA, so the cells are compatible.
The test was more complicated for two males. They took sperm and a male "haploid embryotic stem" cell, and an egg with no genetic information. It also required seven genes to be deleted to make it work.
What was the lesson of the test?
Doctor Wei Li, (the doctor who conducted the test) found out that the reason why mammals need sex is because of DNA. Our DNA behaves differently, depending on if it comes from mom or dad. Without a male and female copy, our development won't be complete or successful. This is called genomic imprinting – parts of DNA in sperms and eggs get different stamps which affect how they work.
The bits of the DNA that carried these stamps were deleted so it will be possible to make baby mice possible.
Doctor Li said that this test made them see what's possible: the defects in 2 female mice can be eliminated while the defects in 2 male mice can be crossed.
Can a same-sex couple have babies?
A doctor from the University of Auckland, Doctor Teresa Holm thinks that it may be possible in the future. She thinks this research might lead to progress in terms of reproduction for same-sex couples. However, it can only be allowed the moment the scientists are certain that this technology will work.
Despite the success of 2 female mice, others are still not convinced that the mice are all okay. If they really want to push for this, then more research and more tests will have to be done.