That 99% number is wrong.

Additionally, it should set off alarms that the argument implies we should give people Down Syndrome.

Using it to argue against helping people with Down syndrome is worse.

The authors spell out why its wrong. [1] Their sample was exclusively from DS nonprofit mailing lists, got a 17% response rate, with a median household income of $100K, (2x median), and as they wrote, the results are likely "a positive overrepresentation" because people with severe problems are least likely to participate.

On top of that, decades of research [2][3][4] document that people with intellectual disabilities disproportionately answer "yes" to whatever you ask them, and this survey had "Yes" as the first option on every scale. If you take the number at face value, people with DS are the happiest demographic ever measured, crushing the OECD average of ~67% [5].

Using happiness to argue against helping people is wrong because it papers over what Down syndrome actually is, a physical ailment. About half of people with DS have congenital heart defects. Alzheimer's incidence exceeds 90%. Life expectancy is around 60 [6][7][8].

And the suffering isn't contained to the individual. My sister was disabled. It consumed my family. Research confirms this isn't unusual: parents of children with DS show significantly elevated stress [9], siblings become caregivers young [10]. A self-reported happiness survey doesn't capture any of that. It's not the whole picture. It's the one corner of the picture that's easy to look at.

[1] https://pmc.ncbi.nlm.nih.gov/articles/PMC3740159/ ; [2] https://pubmed.ncbi.nlm.nih.gov/7231176/ ; [3] https://www.researchgate.net/publication/11551964 ; [4] https://pmc.ncbi.nlm.nih.gov/articles/PMC3044819/ ; [5] https://www.oecd.org/en/publications/society-at-a-glance-202... ; [6] https://pmc.ncbi.nlm.nih.gov/articles/PMC12812862/; [7] https://www.nia.nih.gov/health/alzheimers-causes-and-risk-fa... ; [8] https://www.cdc.gov/birth-defects/living-with-down-syndrome/... ; [9] https://pmc.ncbi.nlm.nih.gov/articles/PMC8911183/ ; [10] https://journals.sagepub.com/doi/10.1177/10848223211027861

CRISPR takes a bold leap toward silencing Down syndrome's extra chromosome