If this were true Chelsea would’ve been born Arnold Schwarznegger.
Well....
However I have my own more relevant anecdote. My daughter, the UTex Law grad, who graduated in the normal three years (of class, she took one year off as an AmeriCorps member) of law school, after being told towards the end of her first year, that she'd never pass the bar but passed it on the first try. I have 3 granddaughters. Two of them identical twins. Both pretty feisty for 7 month olds, like their big sister and their mother. Oh, and their grandma Gata is pretty feisty too. PhD, college department chair. They also have an Aunt B, but no blood uncles on their mother's side.
OTOH, there is I believe something to this in the womb influence, at least after conception. My sister in law, May She RIP, was described by my brother as “thick”, rather than fat, and it was a good description.However all her sisters are long and lean types. The difference? She had a twin brother. Of course there may have been an effect on him too, he’s rather effeminate and is gay, but she was the feisty one of the pair, hands down.