The researchers note that lots more work needs to be done before the spermbots could be tested on people. The researchers are searching for a way to see the motors’ movements inside the body so that they can direct them towards the egg, a feat that is not yet technologically possible. The researchers are also not sure how the woman’s immune system would respond to micromotors introduced to her body. The motors themselves, too, could stand to be improved so that they don’t damage any of the sperm. And while the researchers could see the motors’ utility for procedures like in vitro fertilization, where sperm fertilizes an egg in the lab, they’re striving for an application in the “natural environment” of the human body.