Along the lines of SunBlue's thread on sibs and how a N parent can affect each differently, I've been thinking more about not just the differences, but the patterns associated with both gender (relative to the NP) and birth order.
Some of this seems intuitive, but I don't know for sure. I'd love to hear what you guys think of the following observations & insights I've had on this topic:
When the NP is the same gender as the child, it seems to result more in abuse, either physical or emotional. Partly because it seems easier for the NP to "identify" with the child of the same gender, since in reality he or she CAN only really identify with him or herself. My older NPD sister actually consoled my younger sister when she found out her first baby would be a boy. She told her "I'm so glad I only have girls." The way my younger sister described it, it almost sounded like my NPD sister "chose" to have girls like she had a choice. Could my sister have selectively aborted a son? I wouldn't put it past her.
One more anecdote about my older NPD sister (she's a case study by herself!). Before she met her husband, she was actually best friends with his sister. They appear to have a NM themselves, of course. So the 2nd born/1st daughter of a NM became close friends with my NS. It was a close, but short-lived friendship and finally ended, but not before my sister was introduced to her brother. They were to be married shortly thereafter.
As for firstborns, again it seems to be a critical factor in that they become the initial "experiment" of their NP's. It no doubt starts with a surge in power and self-gratification before it turns to jealousy and abuse as the child starts to grow-up. Same gender / first-born, therefore seems like an evil recipe for duplicating a NP.
For the opposite gendered child of the NP, I think neglect and disinterest are driven by the utter inability of the NP to identify with the child. Maybe I'm being too literal, but for some N's they are so pathological that I'm really not being too literal! In my personal case, I know that it was also my incredible ability to create my own voice at a young age in the face of such indifference and abuse. For this reason I have always seemed "inscrutable" to my NM. My younger sister (the 4th and youngest child) is also "gifted" in terms of her ability to SEE THIS STUFF LIKE I DO, so it seems that she was able to escape my NM's influence and also became "weird" like me. When my younger sister was around 6, my NM went so far as to actually open a children's clothing boutique (that her father gave her the money to start), so that she could among other things, outfit my younger sister like an expensive doll. It is difficult to tell whether she did it more to torture my older sister who had moved on to using the very same GF to shower herself with gifts (she was college age at this point.) My maternal GF was actually supplying 3 generations of NPD's simultaneously! His wife, daughter, and granddaughter. At least my little sister escaped the curse.
RIHE