A 板块｜小众选择，可能很快进入普通家庭
For now, the debate is a niche concern. The startups mostly cater to the rich, famous and odd. Yet that will change. A wave of investment means that the cost of IVF is likely to fall. If offered embryo screening at the same time, many couples will take it. One survey suggests that three-quarters of Americans support screening embryos for diseases; about a third say the same for non-disease traits. And that is before competitive pressure kicks in. Who wants to see their child bested by genetically selected classmates?
There are indeed reasons for caution. Polygenic scores are tricky. For many diseases caused by a single gene, testing offers near-certainty: if an embryo has the material, it will develop the condition. Yet an assessment of multiple genes leads to risk estimates, rather than a binary answer—and such estimates are more accurate for people with European ancestry, because they are better represented in genetic databases.
B 板块｜技术有边界，政策未必需要一刀切
Further caveats are in order. Risk reductions can look large in relative terms but be small in absolute ones, particularly for rare diseases. Selecting for some traits may raise the risk of other less desirable ones. Even for highly genetically determined traits like height, parents remain limited by the range found in their own embryos.
These facts are an argument for disclosure, however, rather than legal restrictions or outright bans. If companies want to offer polygenic scoring, they must adequately communicate the technology's limits and risks. They should also let their tests undergo independent scrutiny. This will not scupper a nascent business, since the startups are not, as some critics allege, selling snake oil. A study in 2019 found that parents choosing from among ten embryos may be able to boost their child's height by 1-6cm and IQ by between one and seven points—with tech that is now nearly a decade old. As genetic databases get better and cover broader populations, and AI draws out the relationship between genes and traits, scores will improve.
