It’s not the kind of question that comes up on a first date, or the sixth or seventh, or for some couples, possibly ever — and that’s whether you and your partner share the same recessive gene for an incredibly rare and severe genetic disease that could be passed down to future offspring.

But if Harvard University geneticist George Church could have it his way, no one would ever have to worry about that, not before conceiving a baby or afterward. That’s why Church, who is known for his research in gene editing at his Harvard Medical School lab, is now entering the online dating market.

His idea: to include serious genetic disease as part of the criteria on a dating app — by asking users to submit their DNA for whole genome sequencing.

Sound weird?

Plenty thought so after Church, in an interview with CBS’s “60 Minutes” on Sunday, revealed that he is developing the genetic matchmaking tool that could be embedded in any existing dating app. The point of the DNA tool, he says, is to prevent two carriers of the same gene for a rare genetic disease from even meeting in the first place, by making sure they can’t view each other’s dating profiles. That way, on the off chance two people meet on the app, fall in love and have children, they’ll know the baby wouldn’t be at risk of having a hereditary disease.

Church calls it “digiD8.” And so far, it has freaked out a lot of people.

The word “eugenics” screamed across headlines this week. Vice called it a “horrifying thing that shouldn’t exist.” Gizmodo said it was a “dating app that only a eugenicist could love.” And some advocates worried Church was trying to wipe out genetic diversity and people with disabilities altogether. “Ever considered that having a disease doesn’t mean a life that’s [100 percent] tragic or full of suffering?” Alice Wong, the founder of the Disability Visibility Project, wrote on Twitter.

So in an interview with The Washington Post this week, Church tried to clarify what he’s planning to do — and how a dating app encoded with your DNA would work. He stressed his strong opposition to eugenics while insisting his lab values genetic diversity, saying the app would only address a subset of the most severe genetic diseases, such as Tay-Sachs or cystic fibrosis.

“There are a lot of diseases which are not so serious which may be beneficial to society in providing diversity, for example, brain diversity. We wouldn’t want to lose that,” Church said. “But if [a baby] has some very serious genetic disease that causes a lot of pain and suffering, costs millions of dollars to treat and they still die young, that’s what we’re trying to deal with.”

Church is heading the dating-app project with digiD8′s co-founder and CEO, Barghavi Govindarajan, as a self-funded start-up with some investors he declined to name, as the MIT Technology Review first reported after the CBS interview. Under Church’s bio on the start-up’s website, there’s just a quotation: “That is not an outlandish idea.”

He’s been known to make that case for a lot of his provocative ideas — the timelines of which are not always clear. Church — who apologized this year for accepting about $500,000 from multimillionaire sex offender Jeffrey Epstein between 2005 and 2007 — has been saying throughout the past decade that a woolly mammoth could be brought back from extinction, or he could reverse the aging process in humans. Both of those projects are still underway at the lab, the latter of which is being tried on dogs, he and Harvard students told CBS.

By contrast, he said all the technology is already available for the dating-app tool. Now it’s just a matter of finding a matchmaking service that actually wants to do this.

Pushing back on the eugenics comparisons, Church said the foundation of his idea is in genetic counseling, which offers couples preconception or prenatal genetic testing to check whether their baby could be at risk of inheriting a disease.

Embedding that into an app would work like this, he said: First, you would submit a sample of your spit to a lab for whole genome sequencing. Church gave inconsistent numbers of genetic diseases that the test would screen for, at first saying 120 to 3,000 but then settling closer to 120. The results of the test would be encrypted and confidential, and not even you, the user, would get to know your results or the results of others, Church said. The rest would work just like normal online dating — you just wouldn’t see a small fraction of dating profiles.

“About 5 percent of children are born with a severe genetic disease, and so that means you’re compatible with about 95 percent of people,” Church said. “We’re just adding this [tool] to all the other dating criteria."

Several bioethicists The Post spoke with said they would hesitate to compare Church’s project to eugenics, which included state-sponsored forced sterilization, mass killings or imposed breeding throughout the late 19th century to the 1970s. “Eugenics is a strong word,” said Barbara Koenig, director of the University of California at San Francisco’s Bioethics Program.

Rather, both Koenig and Mildred Cho, a professor at Stanford University’s Center for Biomedical Ethics, said digiD8 reminded them of the digital version of Dor Yeshorim, an Orthodox Jewish organization based in New York that beat Church to the idea by a few decades. Church has cited the group as an inspiration.

The nonprofit was founded in 1983 as a response to higher rates of Tay-Sachs — a fatal genetic disorder that destroys the nervous system — that was devastating certain communities, such as Ashkenazic and Sephardic Jews. Before marrying, couples can go to Dor Yeshorim for genetic testing. To avoid stigmatizing people, the organization does not tell couples anything about their genes, just whether they are compatible. “This is especially important in societies where there’s less reliance on termination [of a pregnancy],” Koenig said.

In its earlier days, the group faced virtually all the same questions and uncertainties from critics that digiD8 is encountering now. Even a decade after Dor Yeshorim was founded, the New York Times asked in a 1993 headline: “Nightmare or the Dream Of a New Era in Genetics?”

Cho said she could understand why people reacted so negatively to Church’s idea, fearing a slippery slope or unintended consequences to the genetic technology. For now it’s a dating app, but how else might others harness genetic technology in a way that could further invade lives? To Church’s critics, digiD8 is already over that line.

“I don’t think those fears are completely unfounded,” Cho said. “I think what people are reacting to is this sense of kind of genetic determinism, and this idea that somebody’s DNA can somehow make them ‘incompatible,’ as if all their other personality traits and behavior really isn’t as important as their DNA.”

But for Koenig and Cho, the other big question, aside from whether this will work, is whether people would even care to use it. Do people even want this in their dating app? That’s a question Church said he’s trying to figure out as well.

“An app seems silly to me,” Koenig said. “People don’t fall in love and marry and have children based on purely hyper-rational decisions.”