[mftrhu]

Yes, they would. They do. People express regrets all the time, and that does not make them monsters. They are human, and as much as they might or might not love their child they can acknowledge that their life would have been easier, better, less stressful without one.

[objektif]

Totally agree but as far as I understood op meant about acknowledging publicly like the study in the article. I have never seen anyone openly saying they regret having kids. Particularly in the US I would challenge you to find an example.

[mftrhu]

I have, publicly and less than publicly.

A study would usually fall on the less than publicly end of the axis, since one's answers are anonymized, only read by the researchers themselves - no-one else gives a fuck about them, usually - and even the anonymized datasets hardly ever get published.

It's not difficult to admit "actually, I feel like I should have had kids" to a medical professional. It's even less difficult to admit it on an online form, especially one by an entity you trust - which will perforce be the case - claiming your answers will be anonymous. It's not like the general population cares that much about privacy, after all, and here they would have nothing to lose by admitting regrets about being childfree.