It’s a positive sign, but there are concerns. Ultrasound exams showed that the test embryo is smaller than expected and isn’t guaranteed to lead to a successful birth. Scientists also have to wait for permission from Kenya to harvest the northern rhinos’ eggs. While the government backs the plan, it’s not certain how long the approval process will take.

If this does work, though, it could have a dramatic effect on conservation strategies. Species are going extinct at an unprecedented rate. This technology wouldn’t solve underlying causes like climate change or excessive hunting, but it could prevent outright extinction and help endangered populations bounce back.