I read this book back in the early 90s. I think the cover had a pale tan/peach color background, with two people on the cover, both with eyes that were glowing, or at least solid white.
It was called something like "The Perseus Factor". I only remember some snippets from it:
- I think one of the main characters was a detective hired to investigate a disappearance.
- There are two aliens, and at one point they have sex, but instead of touching, they lay on opposite sides of a bed/table/device, and touch a projection of the other above them.
- Someone, I think one of the aliens gets killed in a fight. I remember a snippet of dialog about the light going out of their eyes, and I think it was literal light, being aliens and all.
- The aliens had implanted alien hybrids into human women, and they were retrieving them. They always refer to them as zygotes.
- At the end, a message gets sent to the alien homeworld/mothership/something, and the ending dialog says that it'll take ten years for the message to be received, and another ten for the aliens to arrive.