Some argue that the Sons of God could not be angels because:
A major theme of the Old Testament is the negative outcome of believers intermarrying with unbelievers.
Angels are spiritual beings, and therefore not reproductively compatible with human women.
Advocates of the Angel-hybrid position hold that:
Angels are recorded on two occasions in Scripture as eating food, therefore they have some ability to interact with the material world.
Angels can at times be indistinguishable from human beings, and "some have entertained angels unawares," (Hebrews 13:2)
The sexual immorality of Sodom and Gommorah is described as "likewise" in comparison to the actions of the angels that "left their proper dwelling" and that Jesus has chained in darkness until Judgment(Jude 6 & 7).
We really don't know what angels can and cannot do, as we lack the ability to capture and study them, and Scripture says little about them.
The question should be decided by the context and evidence rather than a preconceived idea about the nature of angels.
The Augustinian position fails to explain the production of gigantic offspring from the union of believers and unbelievers.
The unanimous position of Jewish and heathen authors prior to Philo of Alexandria is that the angels came down and sired children with women.