This post is building on the ongoing conversation about Judith Bennett's History Matters. See part 1, part 2, and part 3. Thanks to Notorious for starting this up--great idea!
First off, I think this is a great book, immensely thought-provoking. I should also clarify that I read the book a year or two ago, and now can't find my copy, so I haven't fully refreshed my memory.
But, as I remarked in the comments to Tenured Radical's post, I have some concerns about the use of "lesbian-like" to describe medieval women, particularly medieval nuns. I can see the attraction to the term: nuns did, after all, live in primarily-female communities, and so often had their closest relationships with other women. Bennett's discussion of the term also reminds me of the need to avoid heteronormativity, which can be easy to slip into.
Nonetheless, I have some qualms. One is that I've encountered a number of people who were already eager to assume that medieval nunneries were hotbeds of women having sex with each other. Many of them were undergraduates, true, but not all; I fear that introducing "lesbian-like" only reinforces some of the more titillating notions about medieval nuns. That alone wouldn't put me off, though.
Second qualm is that women's monasteries in the Middle Ages were, in fact, not always, or even typically, female-exclusive communities. Nuns had male chaplains, confessors, and other priests on hand; some nunneries had attached communities of lay brothers; lay men did construction, farming, or other manual labor around nunneries. So, at many communities, men went in and out quite regularly. Plus, while many nuns, perhaps even most nuns, did have their primary emotional relationships with other women, there must have been many nuns who viewed men as their primary friends and emotional supports. Hildegard of Bingen's male secretary, Volmar, seems to have been a trusted aide and confidant; Elisabeth of Schonau was very close with her brother; numerous later medieval nuns had strong emotional ties to their confessors. So even on the level of emotional, rather than sexual, intimacy, many medieval nuns had important relationships with men.
Even beyond that, nuns were supposed to direct their energies--emotional, sexual, and spiritual--toward God. Much spiritual literature aimed at nuns invoked the image of a nun as Christ's bride. As I've discussed before, this was not just metaphor, but literalized. Many people, including a great many nuns and their spiritual advisors, viewed nuns as the literal brides of Jesus, the heavenly bridegroom. Nuns' relationship with Jesus could be somewhat eroticized as well as emotionally affecting and intimate. (A digression: what would that have been like for a nun whose sexual desires were for women? would she have found the bearded Jesus on the cross alienating rather than fulfilling? might she have fixed on more feminized aspects of Jesus in her personal spiritual journey?) The generally masculine figure of God was, then, theoretically at the center of nuns' existence, which perhaps makes them seem not so lesbian-like after all.
In the area of sexuality, I think a case can be made that, in the Middle Ages, virginity was a sexual identity. Whereas modern secular culture tends to view virginity as a temporary phase of life, to be moved past in one's youth, for medieval people it was a state to aspire toward, to protect vigilantly, to be constantly aware of. The preservation of virginity (or chastity) was a vital part of nuns' identity. How would this affect any sexual orientation on the part of nuns? If a nun had taken vows as a young girl, to what extent was she even aware of her other sexual preferences?
As discussed by Bennett, the term "lesbian-like" does raise some important issues of interpretation and things to think about. But for all the above reasons, I think it's too easy to apply to medieval nuns, and doesn't do enough to reflect the real complexities of nuns' daily lives.