Authorities are investigating a Southern California couple after their infant child was taken to a hospital with a traumatic head injury and 21 children were discovered in their custody.

The removal of 21 children from a Los Angeles-area couple has put a spotlight on the practice of using surrogates to build a family.

More than 20 children are in the custody of a California child-welfare agency while authorities investigate a Los Angeles-area couple and whether surrogate mothers around the country were misled.