I think the main problem is that something like "science proves generational trauma is real" is a nice headline, so people p-hack it into existence. "Science proves that generational trauma is not real" is just a null hypothesis being confirmed - not a publishable result and nobody cares, so you'll never hear about it. So be very skeptical of nice headlines, especially in university press releases!
I read this study earlier in the week. It doesn’t have a larger sample size, but the way they identified the genes could present problems. They did a whole genome search and found 21 genes with the associated change, across 131 participants. It’s hard to know if f they’ve correctly isolated that the cause is the conflict exposure. There could be a lot of other things going on here. The first group where the grandmothers were exposed all moved to Jordan in 1980, and the other group on 2011. There could be something about moving to and living in Jordan that caused the methylation.
I think the main problem is that something like "science proves generational trauma is real" is a nice headline, so people p-hack it into existence. "Science proves that generational trauma is not real" is just a null hypothesis being confirmed - not a publishable result and nobody cares, so you'll never hear about it. So be very skeptical of nice headlines, especially in university press releases!