The recent firing of Brooke Smith from Grey's Anatomy is a grim reminder that certain prejudices are still ascendant in television, that time-honored rules continue to apply, often to the detriment of actual drama. In fact, when Smith got those first fateful pages sending her character, Dr. Erica Hahn, into the arms of Dr. Callie Torres (Sara Ramirez), she should have made darn sure it was just a single drunken interlude, or an ongoing but unconsummated girl crush. Because most gay characters are allowed to have sex on network television only if they are part of a single-episode story line, and all actively sexual lesbian characters must be sylphlike, gorgeous and preferably under 30. For obvious and irritating reasons.

Yes, complaints that the Erica/Callie romance took a graphic and ghastly turn mid-month, with far too much discussion about the mysteries of the female genitalia, were excruciatingly valid, but how is that Smith's fault? She didn't write all that "south of the border" nonsense. And that was a single-episode problem, easily resolved and much more quickly forgotten than Meredith's drowning or the George and Izzie debacle.

No, I suspect what irked whoever made the call (and Entertainment Weekly's Michael Ausiello said that it was the network's decision, not the show's creator, Shonda Rhimes) is precisely what made the Erica/Callie relationship worth talking about. Not that they were both women - good heavens, how dull - but that they were, how shall we say, average size. With hips, you know, and actual breasts. Not two girlie waifs exchanging a stolen kiss or a grope in the women's room stall over a line of coke, not an androgynous club kid putting her best moves on some sitcom heroine. But two women of substance, physically and psychologically, falling in love and talking about it way too much, the way women tend to do.

As Dr. Mark Sloan (Eric Dane) might say: "Girl on girl is hot. Woman on woman? Just a downer."

Smith probably got the boot not because her character wasn't interesting enough or sympathetic enough but because she, especially when paired with Ramirez, just didn't fit the visual template of Grey's or indeed, of most of network television. She is a character actress, not a tabloid star.

In other words, and they are words I deeply regret, Ramirez, with all her lipglossed lusciousness, may be beautiful enough to be bi, but Smith is not beautiful enough to be gay. At least not on network TV.

Some ground, it would appear, is too calcified to be broken.