Ugh, no.

One can't argue that personality disorders are inherently genetic. You can argue there's a significant genetic component, but to think that someone is just going to be a narcissist despite how you would rear them is... well, bioessentialism.

Edit oh wait sorry. You asked you didn't argue. Everyone is born like that, yeah, like everyone is born without object permanence. Then you develop it very early on. Just like you develop a sense of self-criticism as your cognition grows. Some just never do.

I would have guessed this is more of a nurture situation, rather than nature