Illustrations by Spencer Olson

My Two Dads?

Science is racing toward figuring out how to let two men procreate biologically

It has long been parodied in movies and TV shows like Junior, Three Men and A Baby and My Two Dads, but the prospect of two men creating a shared biological child is quietly inching closer and closer to reality.

Though it could take years, if not decades, before the technique is perfected and brought to market, teams of scientists and fertility experts across the globe are working to master what will be the greatest leap forward in fertility science since the in vitro fertilization revolution of the 1970s, and are optimistic as more and more hurdles are cleared.

Last year, scientists at Cambridge used human embryonic stem cells to create primordial germ cells. This is significant because primordial germ cells— — which have the potential to become eggs and sperm—had previously only been created using cells from mice. The next main hurdle will be to do the same thing in primates.

Though the science is moving in the right direction, seismic shifts in reproductive technology have historically been met with vociferous public debate over the moral and ethical implications. In the 1970s, the government placed limits on funding for IVF research and today, the government has strict limits on how its funding can be used in experiments concerning the creation of artificial gametes (allowing countries like England, China and Canada to become leaders in the field.)

We spoke with Dr. Amander Clark, a professor of molecular, cell and developmental biology at UCLA and member of the UCLA Broad Stem Cell Research Center, about how the work to make this procedure a reality is unfolding.

Okay, so how the hell does this work?
We don’t know exactly how it is going to work yet, but the grand plan is to be able to take skin cells or blood cells and to reprogram them, using molecular biology to convert the cell back to an embryonic type of state and then to differentiate it into male germ line cells.

How close are we to allowing same-sex couples to have a child?
There are reasons why male germ cells have a Y chromosome and why female germ cells don’t, and so getting over some of those big genetic challenges is very challenging. Usually egg cells are made with cells that have two X chromosomes and sperm cells are made with cells that have an X and a Y; as it turns out, that Y chromosome is really critical for making a male germ line cell. It would theoretically be possible to make a female-like cell, which would be missing the Y from a male germ cell, but you would have to figure out a strategy to remove that Y safely. That would be a big hurdle.

But it’s been tried on mice and it worked, correct?
Yes. Recently the mouse model was used, which is one of the preeminent models for mammals. That study demonstrated that you can make functional sperm from stem cells.

“It’s so refreshing to see that, you know?”

What is the next step?
So far, only one scientific research group has demonstrated that you can go all the way from a very primitive stem cell to making a sperm cell in a dish that could be used for reproductive purposes. So the first thing is that an independent group not associated [with that group] should be able to repeat that experiment using the mouse model. And if that happens, the next experiment would be to move to the primate model, so you can repeat the procedure with a species that is more closely related to humans. You would never jump from a mouse model to a human model straight away.

How much time do we have to wait?
This is uncharted territory, so: Do we need to wait for one generation or do we need to wait for 10 generations? So we are talking about the lifetime of a primate — which is much shorter than that of a human, but we are talking in the range of decades.

So we shouldn’t start lining up quite yet?
No. If things go perfectly, we are looking in the next 20 to 30 years, but I don’t think it will be in the next five years. Science takes you in directions you can’t expect, so sometimes it can go faster than you anticipate and sometimes it can go slower.

What kind of hardware do you need to execute this procedure?
You need sophisticated laboratory equipment to be able to perform these experiments, and you need very specialized training — these are not the sorts of experiments that hobby scientists could re-create in a hobby laboratory.

But what’s to stop a rogue researcher with enough backing to do this now? Could this be going in a less-regulated developing country already?
The cost of doing science is tremendously expensive, so I would find it hard to believe that in one of these countries that you describe, they would want to put their resources in this direction. I think that that is more science fiction than reality. I think that the approaches that we’ll need to do this experiment well and correctly can only be found in large university or pharmaceutical biotech settings.

Is there a race to figure this out?
In science there are always races, and this is a very important problem in today’s society, at least in developed countries. I would say that in the sciences there is a race to be able to demonstrate which group in the world is going to be able make a germ cell either male or female entirely in vitro that is shown to be functional. But it’s a long race.

Why isn’t the United States taking the lead in this research?
The U.S. is very competitive — up to a point. Where federal funding stops in the U.S. is once you have a male or a female gamete that you have made in a dish, once you have those, you cannot fertilize them. You can’t see if your male/female sperm or egg cell will be fertilized or not — that is something that the NIH will not fund.

But that is where private funding steps in, correct?
Yes, that is absolutely correct.

Do you see any parallels with the stem cell research and the IVF movement of the 1970s?
I think that there are really good parallels and lessons to be learned from the IVF movement. In the United States the polling suggested that Americans were not in favor of IVF, so it really put the brakes on the research that was being performed in the U.S. — and even the fact that U.S. scientists were not the first ones to make [the first IVF baby] was largely due to the fact that the public opinion was not in favor of messing around with natural reproduction.

After Louise Brown was born in the United Kingdom, the public opinion in the U.S. completely reversed, and so I think what that tells you is that U.S. citizens are more conservative on their opinion on science and the way science changes. They want to see tangible evidence that something is going to work before they are in favor of it.

Are you confident that the scientific community can win over the unimaginably staunch resistance to this?
It is absolutely true that the moment you start to change the way reproduction happens naturally there are groups who would be very opposed to this. That said, there is a large faction of the U.S. population that suffer from infertility, so they are looking for options, and it is that group of people who would be the best advocates for this technology once it worked.

Peter Kiefer is a Los Angeles-based writer. He previously profiled the football trainer who’s turned sprints and drills into a spectator sport for MEL.