Yep, but they aren't just her flesh. Those sons are the result of a combination of DNA from the father and the mother.
Since God is Spirit and has no flesh, there is no God "DNA" in Jesus' flesh, which means God created the flesh of Jesus in the womb of Mary. He may well have used some of her DNA to do so, but it wasn't all hers.
This is an extrascriptural explanation, and it strikes me as heretical. If there had been some man's DNA mixed in, then that would have given Jesus at least a virtual human father.
At any rate, I don't think Al is making a biogenetical point here, but rather that it pleased God to have a human mother, when He could have incarnated in some way that would avoid a human mother just like He was born without a human father.