When researchers castrated a male rat, implanted a uterus into the animal, surgically joined its circulation to that of a female rat, and transferred embryos into the uteruses of each animal, they found that the male could in fact carry a pregnancy. In 4 percent of cases, pups that were carried by male rats and delivered through Cesarean section survived.
The authors of the study, posted as a preprint on bioRxiv on June 10, say that this model could serve as a useful way to study reproductive biology, including identifying key factors in blood that could help maintain pregnancy. But some researchers question the utility of experiments using these highly artificial conditions, and the authors got so much pushback from the scientific community and the general public that they at one point requested the study’s retraction from the preprint server. For now, the preprint remains available.
“While the surgical manipulations ...
