Melissa Francis played Cassandra Cooper. She was adopted by the Ingles when her parents were killed. Melissa Gilbert played Laura (Half-Pint) the second youngest daughter of the Ingles. Melissa Sue Anderson played Mary. They had another daughter named Carrie. They also adopted several orphans.
Oh, and I forgot baby Grace. She was the last baby. Mary, Laura, Carrie, and Grace were their natural children. Cassandra (Melissa Francis) was adopted.