Artificial Sperm Is Coming

Your testicles may soon be obsolete

Welcome to the future: Researchers recently took an important step forward in mimicking how the human body produces sperm, and could one day (likely 10 or so years from now) create artificial, lab-grown sperm and eggs for infertility treatment.

It’s all quite science-y, but here’s the gist, according to The Guardian:

Speaking at the Progress Educational Trust annual conference in London this month, Azim Surani, director of germline and epigenetics research at the University of Cambridge’s Gurdon Institute, said he and colleagues had passed a significant milestone on the path to producing sperm in the laboratory. The team is thought to be the first to have reached the halfway point on the developmental path from human stem cells to immature sperm.

The study hints that one day it may be possible to manufacture sperm and eggs from stem cells or even adult skin cells.

To make sense of this achievement—and what it means for the future of reproduction (and humanity in general)—we picked the brains of Richard Paulson, professor of reproductive medicine and director of the University of Southern California’s fertility program, and Jason Barritt, chief scientific officer and laboratory director at the Southern California Reproductive Center.

How are the researchers attempting to create this artificial sperm?Paulson: Human stem cells can be differentiated into any cell in the body—that includes brain cells, kidney cells and also reproductive cells (like sperm). In this case, the question is: How do you entice a stem cell to become a sperm cell instead of a brain cell, for instance? These researchers created an artificial gonad to help the original stem cell decide to become a sperm.

Normally, these stem cells come from one of two places: There are embryonic stem cells, which come from the inner cell mass of a human embryo. But more often nowadays, we use induced pluripotent stem cells, which can be taken from any cell in the body. For example, they can derive stem cells from a little piece of skin.

What might we use artificial sperm for in the future?
Let’s say I want to reproduce, but I had some sort of accident that resulted in losing my testicles. Scientists could hypothetically take a few of my skin cells, turn them into stem cells, and then turn those stem cells into sperm. From there, I could use in vitro fertilization to become a father.

Here’s another example: If two people of the same sex want to have a child, scientists could make an egg out of one stem cell and a sperm out of another stem cell. Say you have two women: One might use her own eggs, and scientists could make sperm using skin cells from the other woman. This would allow them to reproduce.

Barritt: This could technically be useful for a person who transitioned from female to male, and wants to be able to produce sperm as well. Scientists also would be able to produce sperm cells that could then be used to help figure out why fertility is declining, and what goes wrong. In other words, we could use these sperm cells for research and testing, which is important because we can’t simply take a testicle out of someone for fun.

Are there any dangers that come with using it?
The DNA must be retained in these sperm, which is tricky, because the sperm should only contain half of our DNA. We each have 46 chromosomes—23 from our mother and 23 from our father. So when you create a sperm cell, you have to throw half of the chromosomes (23) away, and there will be problems if that’s done incorrectly. Those sperm would produce nonviable offspring.

Barritt: The things that can go wrong in the process of epigenetics [heritable changes in gene expressions] can lead to things like Prader-Willi syndrome or Angelman syndrome. There are probably many other genes that are important to this process, and if they’re not right, they may lead to genetic issues that we don’t even know about yet.

Would artificial sperm allow people more control over how their child turns out?
Not much more than we currently have. Today, you can go to a sperm bank to collect sperm from whoever has donated, and analogously, you can go to an egg bank to collect an egg from whoever has donated. Artificial sperm might make this process a little easier: These people wouldn’t have to donate sperm or eggs, only their skin cells.

Would it be possible for someone to create sperm from cells picked up from anyone, anywhere? Say, taking a cell from a celebrity without their knowledge?
The idea that this is going to create abnormal children—or that someone might steal some of your skin cells to produce a child that looks like you—is a little far-fetched.

Barritt: You won’t be able to simply pull some DNA from a counter. To go through this process, you would have to give them enough cells to populate the artificial gonad and go through an eight-week process. Of course, there needs to be legal control to ensure no one does anything against someone’s consent. However, you would really have to be consenting and wanting to do this, because it’s a lot of work and will require time and money.

Could this ever become our go-to method for making babies?
The natural way is the human favorite for the time being. But here’s a thought: Aging in women leads to more genetic problems, which leads to a decrease in fertility. The truth is, men actually do go through a very similar process—it doesn’t occur nearly as fast or as harshly, but there is something called advanced paternal age. There’s some literature that claims genetic mutations—like autism—may come from men of an older age, which may be because the cells in their bodies that produce sperm accumulate genetic problems over time.

If men of an older age want to reproduce, they could put non-sperm cells through this process, and therefore it wouldn’t be an older cell that produces the sperm. It would be a nice young cell, which would therefore decrease the potential of advanced paternal age effects. In that way, it may become a standard for advanced-age men.