A service that digitally weaves together the DNA of prospective parents to check for potential disease in thousands of "virtual babies" is set to launch in the US by December.
New York start-up Genepeeks will initially focus on donor sperm, simulating before pregnancy how the genetic sequence of a female client might combine with those of different males.
Donors that more often produce "digital children" with a higher risk of inherited disorders will be filtered out, leaving those who are better genetic matches.
Everything happens in a computer, but experts have raised ethical questions. "We are just in the business right now of giving prospective mothers, who are using donor sperm to conceive, a filtered catalogue of donors based on their own underlying genetic profile," Genepeeks co-founder Anne Morriss told BBC News.
"We are filtering out the donor matches with an elevated risk of rare recessive paediatric conditions." Ms. Morriss, an entrepreneur, gave a presentation on the company at the Consumer Genetics Conference in Boston last week.
She was motivated in part by her own experience of starting a family. Her son was conceived with a sperm donor who happened to share with Morriss the gene for an inherited disorder called MCADD. MCADD (medium-chain acyl-CoA dehydrogenase deficiency) prevents those affected from converting fats to sugar. MCADD can be fatal if it is not diagnosed early. Luckily, in Ms Morriss's case, the condition was picked up in newborn screening tests.
"My son has a pretty normal life," Ms Morriss said, "but about 30% of children with rare genetic diseases don't make it past the age of five."
Genepeeks has formalised a partnership with a sperm bank - the Manhattan Cryobank - and has a patent pending on the DNA screening technology.
The start-up benefits from the rapid pace of change in genetic technology. Indeed, six months ago, Genepeeks' founders decided it was able to use a superior system for DNA analysis (called "targeted exon sequencing") than the one originally envisaged - a result, says Anne Morriss, of falling costs and increased flexibility.
For couples planning babies, other companies already screen one or both partners for genes that could cause disease if combined with a similar variant - so-called "carrier screening".