Fertility technologies and trans-kin altruism

If a couple wishes to have children, is able to have them through the usual biological process, and there are no known genetic problems facing such children, then that couple would be best advised to have biological offspring. In fact, most people would consider this to be simply the natural "default setting" for such decisions. But if they are not able to have such offspring, or if there is a significant probability that such offspring would have some catastrophic genetic problem, then it might be better for the couple to adopt a child not related to them biologically. This would, in the first place, avoid problematic uses of fertility technologies, such as the use of ova from aborted fetuses. But it would also provide an opportunity for the exercise of trans-kin altruism, something which is not always easy to practice but which is an essential feature of our humanity as it has developed through the evolutionary process. That is to say, there are both negative and positive reasons for adoption. Negatively, it may enable us to avoid ethically questionable uses of technology. Positively, it responds to and reinforces a feature of our evolutionary history which is crucial to what it means for us to be human.