Objectivist literature short-changes the important issues of family and children. To many Objectivists children are simply of little personal value - not worth the effort. That's fine, children certainly are an optional value. But there are others who "feel" that children do have value, but struggle to find objective justification. A rational decision to have children must include comprehensive and conscious awareness of the "sacrifices", the time, money, energy and inconvenience entailed in raising them. The nature of children - their dependence on adults - dictates that parents consciously commit about 20 years of responsibility to their offspring. This long term obligation is part and parcel of whatever value children may represent to the individual. What values could possibly offset this price, and can these values be rational?
There are indeed important rational values to be had. One's children can be a precious metaphysical expression of an optimal romantic relationship. A concretized manifestation of merged characteristics of two people who value each other highly. Similar to the romantic relationship itself - but different in form and expression - children can serve to provide what Nathaniel Branden refers to as psychological visibility (see "Psychology of Romantic Love"). Children's presence in a relationship can serve both as a constant reminder of the admirable characteristics of the parents - who as self-actualized adults value themselves - as well as a symbol of the bond, the integration, of the two individual's lives. Naturally, children are also individuals and will not always reflect their parent's values. But even this, the expression of individuality and freewill, can and should be a value to parents; it affirms their objectivist philosophy and demonstrates their highest value, individual human life.
Most (intentional) parents obtain great value from teaching and molding their children - and from just watching human life, this most precious miracle, evolve and flourish. We can also learn much both through the process of teaching our children, and by understanding their often fresh, innocent perspectives of life. This innocence, as well as children's often uninhibited display of love, can be a valuable source of pleasure; provided that one doesn't become dependent on unconditional love.
There is another, more abstract, value to the concept of family. Human civilization and the heights it has and can achieve are not possible without the accumulation of knowledge passed from one generation to the next. This is to say nothing of the obvious necessity of successful human reproduction, without which we would not even be here. Children and family represent in an abstract, sense-of-life manner the importance and value of this aspect of being human. Objectivism has generally not put sufficient emphasis on the value of human relationships, family and society, all of which are essential aspects of what we value in man's progress and greatness. Long-term intellectual evolution can be seen as a basic moral principle that enables improved human survival.
What are some of the common irrational motivations for having children ? Having children by default must be at the top of that list. Default either because it's the "done thing", because your partner wants them, or because you just "let it happen" - a good recipe for unhappy parents and dysfunctional children. While the common value and purpose of children can substantially enhance a good relationship, it is disastrous trying to salvage a bad one by having children. Another common motivation is emotional, the urge or drive to have children even in the absence of suitable circumstances. Whether these ultimately turn out to be genetic or environmental - itching caused by hormones or the pleasant memories of playing "House" as a child - rationality must override these. Conversely though, a "rational" decision to have children, not backed by emotional motivation is even more of a disaster. The fact that birthrates in communities with higher education and incomes decline indicates that this is not a biological urge that cannot be overcome by beliefs, rationality, and values.
What are the limits of value and obligation to the child ? Unconditional love, even for one's children, is a perversion of the concept love. To love is to value; one cannot value rationally without judgment. There may be circumstances where your child's life is more important than your own, but that should not be the norm. It would be normal for us as chosen protectors of our children to risk our lives trying to save theirs, but the conscious sacrifice of our own life as an ideal is derived from an altruist (im-)morality. It is not 'in your blood' to love or die for your children, as the many child abuse cases sadly attest to. To love a delinquent, criminal child is not objective. One may well treasure past memories, actual virtues, or potential relating to the child, but to love an immoral child is to undermine one's morality (This is the same inappropriate emotion as loving a partner one does not like). This does not absolve one from the responsibility to raise the child and to do one's best in trying to help the child become lovable again. Complex psychological questions of the child's insecurity and self-esteem, and how to treat him cannot be addressed here.
Even less than our children can demand unconditional love from us, can we demand it from them. In fact, once they leave us and our responsibility ceases, we should not demand anything from them. In this day and age there is no need to have children in lieu of a retirement annuity or for emotional support in old age. Rather than expecting their obligation to us, we will recognize them as individuals who exercise their own judgment as to what value we represent to them. This love cannot be extracted under the threat of moral or emotional blackmail. They're right: they didn't ask to be born. However, to the extent that we will have managed to help them develop a rational morality, and to the extent to which we as parents have lived up to it, they will indeed value and love us.
To summarize, there are many values that children may represent to us. The rational choice to have children and the assessment of their value to us must be done in the context of the long term commitment and conscious appreciation of both the pleasures and "sacrifices" raising children entails. There is no guarantee that we will always love our children or that they will love us. By the choice to have children we assume responsibility for their existential and emotional support, their safety and education for the long term. If the projected values we obtain from having them substantially outweigh the negatives, then there is no sacrifice. The fact that there are no guarantees, is no different to "sacrificing" free time or luxuries to a business venture that is projected to be of great value to us. Irrespective of the outcome, we should do our best to get the most out of the building experience. Life is about the journeys as much as its destinations.