We’ve made babies pretty much the same way for a very long time. No need to get into the specifics, but for the majority of people throughout human history, sex and reproduction have been inextricably linked. But, according to Hank Greely, a professor at Stanford and author of "The End of Sex and the Future of Human Reproduction," that all may change — and sooner than we think.

“In 20-40 years, most babies born to people with good health coverage anywhere in the world will not have been conceived in bed or in the backseat of a car, but will have been conceived in a clinic,” Greely said.

That isn’t to say that people will stop having sex, but Greely thinks that a lot of us won’t be having sex to make babies. Instead, we’ll be using a combination of new technologies that will take reproduction out of the bedroom and into the lab. This move might seem troubling to some, but Greely believes that it’s important to consider this future before it arrives.

So what will this technology actually look like to prospective parents? Well, in Greely’s view, a couple would go to a clinic, and a medical professional would take a skin sample from a woman. This skin cell would then be turned into stem cells (specifically an induced pluripotent stem cell), and those stem cells would be made into egg cells. These egg cells would be combined with sperm (which could also be made from skin cells) to form embryos. A bunch of embryos would be created (Greely roughly estimates 100), and each one would receive a whole genome sequence.

By examining the embryos’ DNA, parents could find out if each embryo was susceptible to genetic diseases or predisposed to health risks. Parents could then select the embryo with the highest chance of leading a healthy life, and bring that embryo to term. Then, voila — a new human will have been brought into the world.

This may sound a bit sci-fi (to be specific, it sounds like Gattaca), but the technology Greely is talking about is, in one form or another, on its way. Thousands of babies are born via in vitro fertilization every year. We’ve already been able to sequence the human genome, and we’re learning more about the mysteries of our DNA every year. Research into the potential of induced pluripotent stem cells is progressing. Greely envisions the cost of sequencing going down and our ability to extract and use stem cells going up.

Now, obviously, there will be issues and objections. For one, ensuring that the procedure is safe is vitally important. Greely raises another point: if people in the future are able to select against genetic diseases, are they telling people with conditions like Down Syndrome that they shouldn’t have been born? There’s also the slightly disturbing idea of picking children based on their genetic makeup — and that isn’t even considering the various religious and philosophical objections. Which is precisely why Greely believes we should be thinking about this transformative technology now.

“Sometime in the next 20 to 40 years, this is going to happen,” he said. “It’s going to change how we have babies, it’s going to change the world we all live in … it’s important.” And if we think about and worry about the implications now, then we are less likely to create catastrophes.