For purposes of sections 17a-116 to 17a-119, inclusive, and subsection (b) of section 45a-111, a “special needs” child is a child who is a ward of the Commissioner of Children and Families or is to be placed by a licensed child-placing agency and is difficult to place in adoption because of one or more conditions including, but not limited to, physical or mental disability, serious emotional maladjustment, a recognized high risk of physical or mental disability, age or racial or ethnic factors which present a barrier to adoption or is a member of a sibling group which should be placed together, or because the child has established significant emotional ties with prospective adoptive parents while in their care as a foster child and has been certified as a special needs child by the Commissioner of Children and Families.