Are the characteristics of the child determined by the soul’s own karma or the consciousness of the parents at the time of conception?

From: Nandasuta govinda das, Bahrain

I read in your article under Sex that the mood of the couple will determine the nature of quality of the child. My question is whether Karma of the offspring will determine the characteristics of the child or the mood of the parents. If the mood determines than what is the role of individual Karmas.