Yes, until age 26 (extended coverage may be available for handicapped children). Eligible dependents include:

• your natural children,
• your adopted children (and those placed for adoption),
• your stepchildren,
• Children for whom you have legal custody and who live with you in a parent-child relationship and who are dependent upon your support and maintenance (such parent-child relationship shall not be considered to exist if either of the child’s parents also resides with you).