Caring for children is very demanding and it is 24/7. A lot does depend on the age of the children and how others help you care for them. Some impairments play a bigger role than others. For example, if your impairments affect your ability to walk, stand, bend, grasp, push and pull, etc then there are some things that you would have to have others to do for you when caring for the child. Having mental impairments can also affect a person ability to care for children. If someone helps you care for your children, how often, for how long and how they help you is important. It would be a good idea for the person to fill out a Third Party form. Medical and non medical evidence and the details of how your impairments affect your ability to functions is vital. Most people with children under 18 are under 50. When someone is under 50, if SSA finds that they can't do their previous work, they look at their ability to do jobs in the national economy.