'Pregnant Man' doesn't deliver much depth

The idea of a man getting pregnant and giving birth is fabulously provocative. It implies some kind of biological miracle. No wonder America has been a little bit obsessed with Thomas Beatie, the "pregnant man," the guy in the People magazine photos with a hairy belly and a massive baby bump. He represents a challenge to the very basics of human reproduction.

Of course, it's a little inflammatory to call Beatie "a pregnant man." The more accurate description would be "a pregnant female-to-male transgender who identifies as a man but whose female reproductive organs are intact," but that probably wouldn't sell as many tabloids or draw as many viewers to "Oprah," "20/20," or, tonight at 9, the Discovery Health documentary "Pregnant Man." When it comes to grabbing eyes, detailed descriptions can be inconvenient.

But in truth, "a pregnant female-to-male transgender who identifies as a man but whose female reproductive organs are intact" is really fascinating in itself. Yes, Beatie is of interest scientifically, to a small extent; he stopped his testosterone treatments and used artificial insemination. No miracles there. But on a social, psychological, legal, and moral level, he is a walking, talking Rorschach. He represents an eye-crossing twist on long-held notions of gender and identity. He's one of the year's great tabloid photo ops, for sure; but he's also one of the year's great opportunities to think about what makes up a man, a woman, a marriage, a mother, and a father.

As Beatie puts it in the Discovery Health documentary, "Does a penis make a man?" Alas, "Pregnant Man," does not go very deep at all on such matters. The hour is a cheery newsmagazine-level primer on how Thomas and his wife, Sarah, got pregnant, became famous, and had their daughter, Susan.

There's plenty of footage of Thomas's naked belly, naturally; that's the money shot that doesn't stop giving. And then we finally see Thomas in the delivery room in labor ("He's taking it like a man, as they say," notes one of the documentary crew members.) But why are people so taken by and distraught about the Beaties? What buttons are getting pushed so hard as to inspire hatred and disgust from the likes of Fox News and strangers on the Web? Maybe someday PBS will take that one on.

"Pregnant Man" also doesn't bother enough with the Beaties' motivation for going public, staying public, and making money on their baby-making. (By the way, Thomas recently announced he's pregnant again.) Are the couple sincere about feeling pushed into the limelight? Do they truly struggle to avoid the always poised-to-pounce paparazzi? Inquiring minds want to know.

Matthew Gilbert can be reached at gilbert@globe.com. For more on TV, visit www.boston.com/ae/ tv/blog.