One is named as being the main culprit - Azazel - and he is mentioned in the bible as the one to whom all sin is ascribed. (A definition of the real meaning of the word sin would be useful, but not relevent to this board as this is where the confusion starts with biblical study and it's resulting doctrine) Anyway, Azazel is equated with satan (adversery), and is not the same as angels who are messengers with other tasks. In biblical and apocryphal literature, there are many different classes of what we term "angels" all of which are as different from each other as beetles from humans....a very interesting subject.
The bible says angels in heaven do not marry, this doesn't mean they don't have bodies or sexual organs or desire. The angels who visited Abraham ate and drank with him and looked just like normal humans. To eat and drink requires a fleshly body. They were also clearly male. Theologians have however stated that angels are incapable of procreation or sexual appetite.