Under the Healthcare Reform Act of 2010, children are allowed to stay on their parent's health plan until they reach the age of 26 regardless of whether they live at home, attend college or get married. Until October of 2010, most health insurance companies stopped coverage for children when they reached an age between 18 and 25, but the children were still required to be dependent and living in the parental home or attending college on a full-time basis.
HRA 2010 means that children can remain on the health plan of their parent even if they are employed and self-sufficient, unless health insurance is available to them through their employer. As long as an alternate health care plan is not available, the children are eligible for coverage no matter where they live or what their status may be.
However, it should be noted that the new law does not require insurance companies to cover the the offspring of children. This means that your 22 year old daughter can be covered even after she gets married, but that her newborn infant may require coverage from another source, such as private health insurance or government health care assistance programs. Even if the pregnancy occurs during the daughter's coverage, health benefits are likely to extend only as far as childbirth, so that prenatal care and delivery are paid for but any medical care the baby needs after it is born would not be.