This is an age old question, I believe, and can be considered in the broader context of why does God cause or allow tragedy and difficulties in people's lives. I don't know how much God causes or how much He merely allows, but being God, he could prevent all of it. But, He doesn't want to prevent it all, as that would deny purpose of life.
It's good to have a father and a mother. It is good to be safe. It's good to be healthy. I believe all of these are ideals we should work for. I should wear a seat belt. I should not take unncessary risks with my life. I should want to live and want to be safe and want to be healthy. But, God in his infinite wisdom, may decide that it will be best for me not to have one of these. He may give me a serious illness, or take a parent through death or divorce, or He may give me parents who don't love and care for me. God might cause this to happen or He may merely allow it to happen. Things like this happen for our own good and we should trust in God's wisdom. Now, the fact that God may allow a 16 year old to get in a serious accident and permanently lose physical capacity, does not mean that we should behave with disregard for our own safety. It would be foolish to think, "Well God obviously does not care about human life because he allowed this child to die in infancy, so it doesn't matter if I care about human life". Similarly, it's foolish to think that because God does not always provide a father and a mother for a child, that having a father and a mother is not something God always wants us to strive for.