It is unclear.

Christian Apologetics and Research Ministry

Can angels have sex with people? | Christian Apologetics and Research Ministry

We do not know for sure if angels can have sexual relations with women because the Bible doesn't tell us.

No

ministrycenter.blogspot.com

The Word of the Lord: Is SATAN Real???

Therefore the notion that Satan or angels can have sex with humans is a notion stemming from movies such as Rosemary’s Baby, as well as error regarding giants called nephalim in Genesis.

The Word of the Lord: Is SATAN Real???

As spirit beings, they do not have the physical characteristics to be able to procreate.

katrael.wordpress.com

Angels That Make It With Women « Katrael's Blog

This may be true although I don’t believe it.

Angels That Make It With Women « Katrael's Blog

There is no Scriptural or biblical proof of this.

Yes

johnthebaptisttv.com

JOHN THE BAPTIST TV - Revival, Repentance, Reformation - Andrew Strom, Paul Washer, Ray Comfort, Leonard Ravenhill

I haven't had the time to read all of the posts but I do believe there is biblical proof that angels can have sex with humans and produce off spring.