Phoebe Desmond is an engaging narrator and she gets us off to a laugh-out-loud start. "It looked like a part from a Milton Bradley board game," she says of her ejected IUD. And when her ever-hopeful gynecologist asks how often she and her never-named beau have, uh . . . , she answers, "I've been averaging three times a day." So Phoebe, 19 and a senior at Yale, is -- no small wonder -- pregnant.

The baby's father is a cad; the minute Phoebe makes mention of having visited the doctor, he decides their relationship is "too intense." A scant six hours later, Phoebe finds him with a silky-voiced someone new.

Phoebe's response is quite wonderful: "Falling immediately out of love with him, I looked into his sly hazel eyes for the last time, and I will go to the grave knowing that he'll never know he had a baby."

But what is she to do? She doesn't want to have an abortion and she doesn't want anyone at home to know. Fortunately for Phoebe, her best friend, Marlys, is the toast of Paris, a headliner at the Folies Berge re. There are worse places for having morning sickness, right?

Marlys, figuring pregnant is safe, farms Phoebe out to Ben, an expatriate painter. Ben is not the only temptation. There are also the Greek boys who work for Ben's landlady -- Apollo, for one. "Apollo had lips like Sophia Loren. He had blue-black curls, skin like marble, and eyes the color of the Aegean. Either that or aquamarine contacts."

But Ben prevails: "At Yale it had taken two meetings. In Paris it was taking two seconds. I was in love with this Ben." She tries to fight it, but circumstances don't make it easy. "Avoiding someone who slept in the same room seemed hard at first, but then I thought of my parents."

So far, so very good. Phoebe is just great and we can't wait to hear what she has to say about anything under the sun. Marlys, who is "the exact color of Root Beer Barrels after they're half sucked" is terrific. Even Ben is okay. And let's not forget the promise of the landlady, Madame Besette, and her Greeks. With characters like this, how can a novel go wrong?

By shelving them, that's how.

Because author Mary-Ann Tirone Smith does just that, off and on, in order to bring in what is alleged to be Phoebe's journal. And she doesn't even do this deftly, but with Phoebe pulling the thing out of her duffel bag and Ben asking, "What's this?" and Phoebe offering it to him and us to read.

It gets worse, too. In an effort to create suspense, the journal is broken off with Ben saying, for instance, "I'm beginning to feel a little afraid for Tyrus," and Phoebe answering, "I know."

Very irritating, this. It reminded me of a Broadway musical a professor of mine told me about, in which a dance number was introduced with the incredible line, "Look! Here comes the man with our tap-dancing shoes!"

Not that the journal itself is awful. It, too, has a swell cast and is done in Phoebe's funny, flip style. In fact, the author even manages to connect the journal to the Pregnant in Paris plot in a way that holds up, even though what the journal covers is Phoebe's desperate stand at a New York monument on behalf of the mentally handicapped.

The journal, in fact, is touching and, at the same time, loaded with quotable descriptions and lines. Observations like, "I wish some billionaire would donate enough money so that every mentally handicapped person in America could buy a pair of Converse sneakers." Or, "Does your grandmother use Pond's cold cream? Every grandmother I know has a great big jar of Pond's cold cream on top of her chest of drawers, right in the middle of the doily." Funny, funny stuff.

No matter. It breaks the book's spine. There are other and much smoother ways of passing along the pertinent information in the journal and the reader therefore moves from an initial impatience to the grim suspicion that perhaps this was done to pad the book, lengthen it, make something whole out of scraps.

This is much too bad, because once we have noted this one extreme flaw, we start to look hard and find many: spots of dialogue that are clumsily expository, major characters (Ben, for one) essentially undeveloped.

The maddening thing is, had we not been jerked around so utterly, we might have been too charmed to have questioned anything beyond Phoebe's fresh and irresistible voice.