Furthermore, Lisa Diamond, a researcher from the University of Utah followed a sample of one hundred lesbians over a period of ten years to determine whether there were any changes in their sexual feelings over time.
She found that women who identified as lesbians could find themselves periodically attracted to and sexually active with men, then women, then men again.
For example, not too long ago, the Sambia, an indigenous tribe in New Guinea believed a boy could not reach manhood unless he fellated an older man and ingested his semen.
The books are quite explicit; and since Radclyffe introduces more couples as the series progresses, toward the end, there's far more sex than intrigue, which probably accounts for much of their popularity.
But there's also a more high-minded appeal, something aspirational about the archetype of the honorable agent.
Some women could be having relationships with members of both sexes at the same time.
In fact, only one third of the women who initially identified as lesbians at the start of the research project reported exclusive sexual attractions and behavior toward women over the course of the study.
You'll find several variations on the shelves of your local bookstore, but the best examples of this protector-protectee romance subgenre come from a writer known as Radclyffe.