A girl who wears men’s boxers to sleep is hardly a rarity — but a guy who sports a pink sequined top is.

At least, this is what society considers to be true, says Yale professor, writer and psychotherapist Amy Bloom.

In her most recent book, “Normal: Transsexual CEOs, Crossdressing Cops, and Hermaphrodites with Attitude,” Bloom strings together anecdotes, case studies and excerpts of interviews to examine sexuality and gender in contemporary society. The book, which was published this October, is Bloom’s first work of nonfiction, and blends together her insight as both a psychotherapist and a writer.

Bloom said she became a psychotherapist because she had always had a fascination with life stories. Like the majority of Americans, she said she lacked a firm understanding of the subject she explores in “Normal,” and added that the book changed many of her preconceptions about sex and gender.

“It certainly made me a lot more conscious of my own blindspots and assumptions,” Bloom said.

Bloom still maintains an active psychotherapy practice, though she said she has downsized it over the past couple of years.

But her career as a writer began more recently, when she first began writing and submitting fiction pieces eight years ago. Bloom, who teaches “Advanced Fiction Writing at Yale,” said that becoming a successful author does not just involve luck: one must also read extensively, be willing to fail, and have a good ear for language.

Although she has experience as a psychotherapist, Bloom said “Normal” is not a clinical book. A large portion of her resources came from conversations she had over coffee with those who were willing to share experiences associated with their not-so-ubiquitous sexual circumstances.

“Normal” examines particular facets of gender issues that deviate from what a vast majority of society considers to be normal.

“I don’t find the word [normal] useful,” she said. “‘Normal’ has always struck me as something that people by and large pretend exists.”

In the book, Bloom explains that this pre-judgment comes from a general lack of understanding about why certain people are prone to manipulate their sexuality, whether they do so through surgical procedures or by donning clothes of the opposite sex.

“Most people would like to think things are simple, which is an understandable impulse,” she said. “But people are not simple. Nature is not simple. Nature is rich and complex.”

Bloom said gender-stereotyping is far looser now than it was in the 19th century, but added that the inclination to place people in rigid categories prevails.

The media, for example, serves as a window into how society feels about topics of sexual identity and metamorphosis, she said.

“We haven’t really gotten to the point in sitcoms where we have a wise-cracking, attractive, butch lesbian,” Bloom said.

Similarly, Bloom said society largely still does not consider it acceptable for men to dress in women’s clothes, while women can wear practically whatever they find to be most comfortable or practical.

“Even in the 21st century, people [can] be made so uncomfortable by presentation of gender at all different from what we like to think is normal,” she said.

Because of this desire to be considered normal, Bloom said people conform in order to avoid being ostracized by their peers.

“The idea that any group of people have to conform to a group of social standards — it’s hard to imagine how that wouldn’t do harm,” Bloom said. “We would all be better off if we weren’t so anxious to label some groups as abnormal.”