Jinx sometimes says things like: "I wish there were a license to breed." She intends this to be an expression of annoyance rather than a public policy recommendation. While I generally oppose the idea that I need to ask permission to do anything that doesn't harm anyone, having a child is a responsibility and one that does impose significant costs on other people.
Now, on average I actually believe that more is better with respect to human beings. Disliking a fair number of them does not prevent me from knowing that the more people there are, the greater my income and opportunities (including opportunities to feel superior). Even considering the disadvantages of natural resource scarcity and crowded cities, you cannot be a philosophy professor on a desert island.
But to say that we're all equal and therefore are entitled to an equal right to reproduce does not answer the question of whether in fact we should, nor does it answer the question of whether we should be held liable when our children predictably turn out to be the screw ups that everyone knew they would be.
As long as it doesn't really harm anyone, I agree that whether you reproduce or not is no one's business but yours. But sometimes people are harmed or burdened by your impetuous desire to get your rocks off. I do believe individuals are entitled to take risks, but they are also responsible when things go poorly. And in many instances, a person's life story is all too predictable.
There are of course limits to parental responsibility. There are many things that no one could have predicted, but for those things that were predictable why shouldn't there be liability?
If you pass on a genetic condition or raise your children to be the kinds of persons that impose burdens on others, surely you bear a part of the responsibility. As adults, we do not spring fully formed from Zeus' head. We come from somewhere. And while it is generally a good thing when we take responsibility for who we are, we are certainly not always fully responsible.
I think there are solid pragmatic reasons why courts should not be burdened with apportioning responsibilities in this way, but I also think the world would be a better place if parents took responsibility for their genetic and environmental influence.
You are entitled to consider the joys of parenting as a reason to have a child, but you are not entitled to be selfish at the expense of others. The eighth child of an Amish woman in rural Pennsylvania and the the eighth child of an inner city single mother are very different kinds of decisions. Does liability penalize people who are already in difficult circumstances? Absolutely, but being in difficult circumstances does not seem to be a sufficient reason to impose costs on other people.
There is no need for a license to breed any more than there is a need for taxi or cosmetology licenses, but that doesn't mean that the world wouldn't be a better place if people took responsibility for their actions.