My mother's stepfather was the person closest and dearest to me when I was growing up. He was also the only non-narcissist and non-enabler in my immediate family. So, when sane, normal people are concerned, genes don't generally play a decisive role - these people treat children decently, whether they're related to them or not.
Narcissists, on the other hand, will mistreat any children in their care, whether they're their biological parents or not. So, why does it even matter whether my NF is my biological father or not?
Well, just imagine your run-of-the-mill malignant narcissist in his situation and things begin to make sense. First, our narcissist discovers he is infertile, which is a difficult thing for any man - or woman - to reconcile with, but it is crushing for a narcissist - infertility is one of the most devastating narcissistic injuries conceivable. Add to this injury the insult of his wife's great desire to have a child - if necessary, with another man's sperm. The narcissist grants her this wish, but she is supposed to take the blame for those previous 12 years of infertility. The newly-created child is already proof of his fertility in front of others, but a constant reminder of his lack of manhood (or whatever he might have in his narcissistic mind) to himself.
Can you really claim this situation is not somehow just a bit more complex than the narcissist getting his own child, a potential mini-me?
The malignant narcissist's wife gives birth to a child that looks quite a bit like her and seems to be happy, getting what she wanted and what he might have wanted too, but couldn't have. As a man who has been known to repeatedly do things just to spite others and rain on their parade and ruin it for them, he:
a) becomes the perfect, ideal, most dedicated father ever, bottle-feeding the infant, taking the child out for long walks, helping the mother to such an extent that she barely notices she has a child, for which she and the child are eternally grateful, or
b) out of envy, sabotages the nursing relationship and takes the baby away from the mother to prove that though she may be the biological parent, he can still usurp the child and control her and force her to love him more. The mother consents to this, out of gratitude and guilt, and doesn't complain because, after all, he's spending time with a child not biologically his, and this is so sweet of him. She lets other things go because of this too.
I'd go with b).
What do you think?