Did Abraham have kids with his black maids?

Moses had two sons with his wife named Zipporah. First son, named Gershom, is mentioned in Exodus 2:22.

Acts 7:29 When Moses heard this, he fled to Midian, where he settled as a foreigner and had two sons. (see also Exodus 18:6).

Moses' wife is described as an Ethiopian (or Cushite) woman in Numbers 12:1. Note, however, that there is debate over the issue of whether Zipporah from Ex 2:21 is the same wife as the reference to the Ethiopian woman in Num 12:1. Rabbinical commentary such as that from Rashi believe this woman to be none other that Zipporah and Moses had only one wife.