[Editor’s note: recent medical developments such as growing a vagina in a laboratory, advances in gender prosthetics, creating sperm from skin cells, etc. suggest this article is worthy of re-read and a place in the very Best of H+.]

Recently I made a bet with a member of the Institute for Ethical and Emerging Technologies. That bet sounded to him like I was being wildly optimistic, and he jumped at it, thinking it was a sure bet that I would lose.

That bet was that by the end of this decade, medical technology would be able to change the gender of anyone to the opposite gender, with full reproductive abilities of the new gender.

That probably sounds wildly optimistic to most of you as well, but not to me. To be honest, I think the deck is stacked in my favor. Why? Because we are a lot closer to realizing this achievement than most of you probably realize.

To illustrate, take a look at this recent Wired article, which describes the current ability to use stem cells mixed with the fat from a patient’s own body to grow additional breast mass in women or to regrow breasts damaged by cancer. But that’s really very unimportant, because the real breakthrough is that this can be done for nearly every kind of tissue. It’s still at a primitive stage, but scientists already learned how to “program” the stem cells to become different types of tissue. They’ve made progress in making heart repairs , functional liver tissue, blood, teeth, bone, muscle, and they have even made progress on discovering how to manipulate stem cells to enable them to divide continuously. This is a small sampling of the various breakthroughs made in just the last few years in hundreds of labs all over the world. If you understand the implications of all those various articles, it is easy to see that we are learning how to program stem cells to do nearly anything that our body programs them to do. Each step of learning how to program stem cells leads to greater knowledge of how to control them more precisely.

But stem cells alone are not the only medical advances that are being made. Another major breakthrough going on in the medical field is in the improving abilities we are gaining in 3D printing. Not only have we discovered that stem cells can be programmed to repair already existing tissue, we are using modified inkjet printers to lay down layer after layer of them in a pattern, and to basically “print” biological tissue that will “grow” together into a complete organ.

Another technique being researched is the creation of “Biological Legos” in which stem cells are embedded in a block of “glue” which holds the cells together while they form natural intercellular bonds. Yet another technique is to use an already existing “scaffold” and fill the spaces with stem cells, growing a precisely shaped piece of tissue.

So not only are we learning to tell stem cells what to become, but we are learning how to dictate the shape of the tissues as well. The implications for plastic surgery should be obvious. Stem cells seem to offer us the promise that we will soon be able to restore the human body to the exact same state it was in prior to injury, enable us to regrow lost limbs, grow replacement organs on demand, and even reconstruct missing or lost tissue for reconstructive surgery. Soon, a mastectomy might routinely remove the cancer, and rebuild a healthy breast identical to the one removed. A heart attack might lead to a regenerated heart healthier after the attack than it was before, and even such routine needs like blood transfusions might be made by pulling your own stem cells to create a personalized supply.

But even this is pretty tame once you combine stem cells with the increasing complexity of automation, because a da Vinci surgeon robot is not going to remain under human control for very long. So think about those articles above, about how we are learning to guide stem cells to become nearly any tissue. Think about the day we can tell stem cells precisely what to become, and to grow in precise shapes. Then think about an autosurgeon connected to a sensor system allowing it to make a complete map of a human body in real time, as it is fed a body map for a desired shape. A decade from now, a plastic surgeon is likely to use body modeling software developed by MMOs and VR to enable you to decide precisely how you want to look, and then supervise the da Vinci autosurgeon as it uses your own body fat and skin cells to produce a stock of programmable stem cells, and then performs hundreds or even thousands of minimally invasive microsurgeries to place those programmed cells throughout your body, where they will become extra muscle mass, larger breasts, repair damaged internal organs, etc., allowing your future self the option of “resculpting” your personal appearance.

“But wait,” you say, “wasn’t this article about changing sex? So you’re saying that changing sex could be done this way too?”

Yes. However, just being able to control stem cells to the point that we can dictate what kind of cell they become, and what shape they will have at maturity isn’t all that’s involved. There are additional differences that have to be addressed in changing sex, such as hormones, biological function and reproductive function. But researchers have already discovered how to tell ovaries to become testes. While this is not as easy to reverse as you might think, because according to this study the ovaries apparently have to “fight” to stay ovaries, we are making great strides in understanding these various chemical and genetic “triggers”, including such seemingly unimportant ones as the triggers that promote the growth of blood vessels to various types of tissue. We’re also making progress at creating “artificial” ovaries, and stem cells have been successfully used to give rabbits larger penises.

This means that as we learn to control what a stem cell becomes, we will more than likely learn how to tell them to become male or female specific organ structures as well as more generic organs. With the abilities of cell printers to be able to make internal organs, an ability that I expect to replace organ transplants by mid to late decade, the ability to “print” sex organs seems assured. It’s rabbit penises now, but can you really believe that men won’t pay to get bigger sex organs even more than women pay to have bigger breasts? Especially when it becomes a matter of a single visit to a surgeon’s office that will heal faster than a vasectomy?

So, in a decade, I think it is quite likely that the patient seeking to alter their gender would start by seeing their surgeon, who would take a complete scan of the person. This scan would then be entered in to a program that would allow the patient and the surgeon to transform the patient’s body into the precise appearance desired. Once the body shape has been defined, the program would determine what changes would be needed, the amounts and types of stem cell stocks needed, the minimal surgery needed to reroute the urinary tract, nerves, etc. and then would proceed to extract the samples needed to create stem cell stocks. The creation of the proper organs would then begin, using a 3d printer to create the needed tissues. Once sufficient stocks were cultured the patient would be placed into the autodoc and, as the doctor supervised, be transformed.

It’s possible that even such steps as printing the organs might be unneeded as the autosurgeon might be able to construct the needed organs in situ.

This ability to control stem cells is why I think I’m stacking the deck. We already know quite a bit about how to do so, and the rate at which that we are making progress, as well as the potential uses for controllable stem cells, makes this a medical technology that will be developed much further over the next few years. Regenerative medicine not only promises to help cure such issues as heart disease and spinal cord injuries, but to grow replacement organs, replace missing and damaged tissue, and even to potentially allow such abilities as replacing missing limbs. It’s a vitally important area of research, and as Wired points out, with such “frivolous” uses as breast enhancement, and the eventual penile enhancement so close to market, it’s going to be the biggest medical money-maker of the next decade. It’s just one small part of the numerous advances that will be made in the next decade, but it’s one that is likely to make an enormous change to our social dynamics. Unlike silicone, there is no “unnaturalness” to a stem cell breast enhancement, and I’m certain that the ability to make any size breasts will likely emerge before mid-decade. Combine that with the ability to make bigger penises, which I also expect to come along mid-decade, and plastic surgery is likely to become as acceptable as getting a new hairstyle. As we continue to make progress, and gain further abilities to use stem cells to heal, regrow, or reshape the body, more people are likely to use them to make themselves look more attractive, enhance their bodies, or even to rejuvenate and repair the effects of aging. The potential uses for stem cells are enormous and, relatively speaking, changing someone’s sex is just one small possibility in thousands.

But it’s still something I consider to be a pretty safe bet.