This 2016 Swedish human study investigated the effects of one specific childhood trauma, parental death:
“Parental (G1) death during (G2) childhood predicts prematurity and lower birthweight in the offspring generation (G3). This response is dependent on G2 gender, G2 age at exposure and G3 parity, but not on G3 gender.
Offspring of women who lost their parent at the age of 0-2 or at the age of 13-17 had an increased risk for prematurity.
Offspring of men who lost a parent at ages 8-12 had an increased risk of prematurity.
For women exposed to a parent’s death at age 0-2, there was no significant deficit in their offspring’s birthweight in any parity class. For women exposed at later ages we observed a deficit in birthweight.
Among children whose fathers experienced parental loss..experiencing parental death at ages 8-12 in particular, or at ages 13-17, but not at ages 0-2 or 3-7, did predict having lighter offspring.”
The study design was unable to produce causal evidence for the putative intergenerational effects. An example of the limitations was:
“We had no information about behaviours and biological markers or genes.”
Its findings were best summarized as:
“Our study fails to refute the hypothesis that a male-line epigenetic mechanism exists which may be triggered by trauma during boys’ slow growth period.”
Still, the study had a firmer foundation than did A problematic study of oxytocin receptor gene methylation, childhood abuse, and psychiatric symptoms, which speciously produced politically-correct results from childhood trauma surveys of adults.
http://ije.oxfordjournals.org/content/early/2016/05/03/ije.dyw048.full “Does childhood trauma influence offspring’s birth characteristics?”