Genetics are a social construct

Technically it's the expression of heritable genes that result in both the psychological traits and the epigenetic trauma expression (certain epigenetic markers are switched on or off due to environmental factors, such as famine).

Personal experience fells that parents treat their kids they way they were treated even in absence of the need to do so because propagating the suffering makes them feel better because "it's not MY fault, see... MY kids suffer this too. Societymust be to blame!." (Price is Right overbid sound -bom bom bom-bommm... waaaaaaaaooooo).