As the whole world knows by now, Kim Kardashian is pregnant with her second child, a boy, through in-vitro fertilization (IVF). Apparently, her husband Mr. Kim Kardashian (a.k.a. Kanye West) wanted a boy, or, as he calls it, “an heir.”

To achieve the desired result, Kardashian chose to only implant male embryos (and evidently, it worked). She most likely underwent preimplantation genetic diagnosis (PGD), a procedure which screens embryos for sex characteristics, looking for XX (a girl) or XY (a boy).

In 2012, it was estimated that PGD was used for 4K-6K procedures per year. In 2014, fertility treatment procedures, including but not limited to IVF, were estimated at around 165K+ per year. PGD is used with IVF, so PGD cases comprise between 2%-3% of total fertility treatments.

Interestingly, the U.S. is one of the only countries in the world within which PGD may used for “prenatal sex selection.” In many countries, its use is restricted to medical and chromosome-related issues.

Nobody can yet say if this will become a widespread practice. It does raise some questions about the ethics of calling the shots on choosing your child’s sex. But this isn’t a new concern: New York University’s Director of the Bioethics Program S. Matthew Liao wrote a paper on the subject in 2004 for the “Journal of Medical Ethics” while at Johns Hopkins University. About halfway through the paper, he acknowledges, “As far as I know, no one has tried to use genetic engineering for sex selection.” Things have certainly changed in 11 years. Welcome to your brave new world.