Have you thought about assigning guardians for your child or children in the event that you suddenly passed away? Some parents don't want to consider this, thinking it is very likely both will die at the same time and assuming that the children would be cared for by their own trusted relatives. Of course, the chances your children will need a guardian are quite small. But if it does happen, don't you want the reassurance that they will grow up in the best possible home?
Choosing a guardian is tough, and even more so because most parents don't have the "ideal candidate", and couples may well disagree on what the best choice is. Perhaps your spouse thinks of his parents as the obvious choice, while you think your sister would be better. And it's hard to determine with whom a child would be better off. Your sister whom your children adore, and who lives nearby but whose husband is a nasty piece of work? Your husband's aging parents who may not have enough energy? Or a close friend who you would trust with your life, but who lives so far away your child has only met her once?
If one obvious choice pops up, and both parents agree, the process is easy and you'll just need to talk about the topic with your chosen guardian. If there are several good candidates, a discussion may also be appropriate. Relatives often end up fighting legal battles over guardianship after a situation like that comes up, but it would be ideal if those relatives could all work together in the interest of the child or children, instead of fighting each other. Those who have plenty of people who care about their kids and would rise to the occasion and guide them to adulthood are pretty blessed, actually.
Those who have children who are old enough should also consult them on the matter, asking them with whom they would prefer to live and why. In any case, it's a good idea to think about this either while you are expecting a baby, or later on. Whomever you choose is likely to be more suitable than who the state would appoint in your absence.