(I might think that only) these are included, these unions being forbidden by negative commandment (only); but I would not include unions liable to kareth (cutting-off) at the hands of heaven; it is, therefore, written, to negate this assumption, "hated" "hated."
I might then think (that also included in the halachah of non-favoritism) are a maidservant and a Canaanite woman; it is, therefore, written "If there be to a man … and they bear to him sons" — Wherever there is "being" (see above), the sons are his (and the halachah of non-favoritism obtains) — excluding the above, where the sons are not (halachically) his, (but the mother's).