Having children has a profound impact on one's life. It can bring many values, and prevent (or hamper) the attainment of others. Leaving a genetic legacy is merely one of many possible values an individual can hold. Ayn Rand clearly stated that she wanted all of her time and energy to focus on her work, and that value was clearly of much higher importance to her than any values which might have been obtained through having children (including leaving a genetic legacy).
I would also argue that leaving a genetic legacy is fairly dubious as a rational value. The root of value as a concept is something you act to gain or keep with the end of improving your own life in the long-term. By definition, the goal of leaving a genetic legacy (as contrasted with enjoying being a parent) is necessarily something which is only relevant once you're dead. By the nature of what a value is, it's hard to consider it a rational value at all.
answered Feb 04 '13 at 00:41
Andrew Miner ♦