The tale of the two male penguins, Roy and Silo, who after trying to incubate a rock in the Central Park Zoo were given an egg by a zookeeper to hatch together, tops the list of `challenged’ books again this year:

“And Tango Makes Three,” released in 2005 and co-written by Justin Richardson and Peter Parnell, was the most “challenged” book in public schools and libraries for the second straight year, according to the American Library Association.

“The complaints are that young children will believe that homosexuality is a lifestyle that is acceptable. The people complaining, of course, don’t agree with that,” Judith Krug, director of the ALA’s Office for Intellectual Freedom, told The Associated Press on Tuesday.

In a fun and fascinating story on ‘Gaydar’ in NY Magazine last summer (yes, it exists!) we learned of the breakup of the daddy penguins. And that shed some interesting light on the nature/nurture question:

But for most in the animal kingdom, same-sex pairing is either fleeting or situational. Even Silo and Roy, for six years the poster-penguins for same-sex love in the Central Park Zoo-they famously raised a daughter together-were not destined to last forever. Silo waddled off with a female named Scrappy in 2005, says zoo director Dan Wharton, adding that we shouldn’t worry about Roy’s hurt feelings. “Penguins are matter-of-fact about these things.”

The religious right made sure that I knew that long ago. What I didn’t know was this:

Of course, biology doesn’t determine everything. And some critics of sexual-orientation researchers blame them for minimizing the role of experience in determining our affectional course in life. The feminist biologist Anne Fausto-Sterling has waged a constant battle against their research, which she calls “a big house of cards” that ignores the power of environment in creating personality. Nurture, she argues, can and should be studied as a link to sexual orientation. The baby penguin raised by her two dads [Tango] is a potential case study-though genetically unrelated to either parent, in the last few mating seasons she has mated with another female.

That Gaydar piece had some other interesting things to say about female sexuality:

In many other studies, though, lesbians have appeared less unique than gay men, leading some people to wonder if their sexual orientation is innate. Michael Bailey-who, as a heterosexual researcher, is a minority in this field-even doubts the existence of female sexual orientation, if by orientation we mean a fundamental drive that defies our conscious choices. He bases this provocative gambit on a sexual-arousal study he and his students conducted. When shown pornographic videos, men have an undeniable response either to gay or straight images but not both, according to sensitive gauges attached to their genitals-it’s that binary. Female sexual response is more democratic, opaque, and unpredictable: Arousal itself is harder to track, and there is evidence that it defies easy categorization. “I don’t yet understand female partner choices very well, and neither does anyone else,” Bailey wrote me in an e-mail. “What I do think it’s time to do is admit that female sexuality looks in some ways very different from male sexuality, and that there is no clear analog in women of men’s directed sexual-arousal pattern, which I think is their sexual orientation. I am not sure that women don’t have a sexual orientation, but it is certainly unclear that they do.”

He contends that what they have instead is sexual preference-they might prefer sex with women, but something in their brains can still sizzle at the thought of men. Many feminist scholars agree with this assessment, and consider sexuality more of a fluid than an either-or proposition, but some don’t. “I think women do have orientations, but they don’t circumscribe the range of desires that women can experience to the same degree as men,” says Lisa Diamond, a psychology professor at the University of Utah, who is writing a book on the subject. “For women, there’s more wiggle room. You can think of orientation as defining a range of possible responses, and for women, it’s much broader.”

When I pointed to the Gaydar story the first time, I noted that Bailey is a controversial figure in the LGBT community. He “has notoriously declared that true male bisexuality doesn’t exist and dismissed many transgender people as peculiar sexual fetishists.”

Still, I find the female sexual orientation observation an intriguing one.