Isaac and Ishmael family
Yes, based on the Bible (specifically Genesis 28:9 and 36:3), a child of Ishmael married a child of Isaac.
- Esau (son of Isaac and Rebekah) married his cousin Mahalath (also named Basemath), who was the daughter of Ishmael.
- Esau took this wife in addition to his Canaanite wives after realizing his parents did not approve of his previous marriages.
- Mahalath was also the sister of Nebaioth, one of Ishmael's twelve sons.
This marriage established a familial connection between the descendants of Isaac (the covenant line) and the descendants of Ishmael.