Given the speed at which reproductive technology has advanced over the past few decades, it doesn’t feel all that far-fetched: A future in which anyone can have a baby, regardless of creed or need, whenever they feel like it. Already, in our present moment, one can buy or sell eggs and sperm; we can give embryos genetic tests to ensure the children they produce don’t have any life-threatening hereditary conditions; and babies can even be born, now, with the genetic information from three parents.

So it follows that we should soon be able to to have pregnancy outside the body — artificial wombs. R ight?

You’d think. Scientists have already figured out how to mimic many of the body’s processes for techniques like in-vitro fertilization and even hormonal birth control. But the ways mothers’ bodies support and signal fetuses is incredibly complicated — and the science isn’t yet at a point where we can simulate these processes. And because scientists are prohibited from studying embryos 14 days past their fertilization, that’s one sci-fi vision that is not likely to come to fruition.