https://www.razibkhan.com/p/you-cant-take-it-with-you-straig...
The actual biological reality is fascinating, and so much more interesting than the distorted version you get from unscientific fabulists.
Epigenetics is one way that cells have of turning on and off the genes that are expressed. The same way that you can 'comment' a piece of code out using some special flags.
What is special about it is that it turns out that your mom's experience during pregnancy (and your experience during development) can affect which genes are turned on and off in your cells.
The classic example of this is that children of starving mothers such as during the holocaust, or during other famines, often went on to be overweight, because they were conditioned to be in 'starvation mode' so the genes for uptake of nutrients were more turned on, or the genes for decreasing wastefulness were turned off.
It doesn't take much imagination to see how some of these things could reinforce each other, or alternate, over multiple generations.