There's a moment in Manning Up when Donnie and Raymond, two 30-something fathers-to-be, act out a baseball fantasy involving a home run and over-the-top celebration.

Unfortunately, Manning Up is more of a seeing-eye single at best.

There is a solid concept for comedy at work in playwright Sean Christopher Lewis's Manning Up--a look at how pregnancy affects a man's self-image, and what he thinks it is to be a man. But the characters he's created to relay his concept are so broad, and their relationship with each other so difficult to believe, that it was hard to focus on the occasional insightful gem that came along in the show's 90 minutes.

It's a classic Odd Couple set-up. Donnie (Lanny Langston) is a nerdy nebbish of an English Lit professor who borders on hysteria when he starts thinking of his impending fatherhood. Raymond is an actor and stereotypical man's man, who covers his basement "mancave" where the play unfolds with a mix of sports memorabilia, movie posters (Goodfellas, Scarface) and enough athletic equipment to open a Play It Again Sports--skateboards, multiple footballs, a basketball hoop on the wall and a box full of baseball gloves, among other items. I've been in a lot of mancaves in my life, but never one so well stocked for an impromptu ballgame.

These two unlikely friends seem to have been brought together through their wives' friendship, but over the course of Manning Up, the depth of their relationship is revealed as the two men discuss their fears of the future, as well as some scary moments from the past that fuel their respective neuroses.

The set-up has potential, but Donnie and Raymond are presented as such broad stereotypes--one the ineffectual spaz, the other a modern caveman--that the scenes intended to elicit laughs are often more groan-worthy than funny, and the moments designed to be poignant are harder to buy because the characters are more cartoonish than real.

At one point in the show, Raymond signs the duo up for a nearby "Manimar," where they want to go and find and unleash their true inner males. I was really hoping the second act would find them at the Manimar, if only to get a few more examples of what a "man" is, beyond the two broadly drawn characters. Perhaps an academic that isn't a nerd, or a jock that doesn't come off like a meathead. No such luck.

Donnie and Raymond certainly talk about the different types of men they might have evolved into--or still might, after their children are born. Those discussions make for the most authentic moments of Manning Up. Too bad there aren't more of them.

Manning Up runs at Salt Lake Acting Company through Dec. 9. Tickets and information are available through the Salt Lake Acting Company Website.