Armin Brott, father and writer, says the title of one of the first articles to appear on the subject "should give you some idea of the medical and psychiatric communities' attitude toward the impact of pregnancy on men." Published in the July 1966 issue of the American Journal of Psychiatry, it was called "Fatherhood as a Precipitant of Mental Illness."

Some things in life improve. In recent years, fathers have become a fixture in delivery rooms. But a father's role during the prior nine months remains something of a mystery to most men.

Two excellent books should help: "The Expectant Father: Facts, Tips, and Advice for Dads-to-Be," by Brott and Jennifer Ash (Abbeville Press, $9.95); and "Pregnant Fathers: Entering Parenthood Together," by psychologist Jack Heinowitz (Parents as Partners Press, $14.95).

Heinowitz's book first appeared in 1982, but the new edition is radically revised. "The role of the father has expanded in recent years, and I wanted to address that," he says. After the first edition was released, Heinowitz was surprised by a barrage of critiques and accusations: "Are men really pregnant? Doesn't this wording detract from the woman's experience?"

Lexicographers need not be alarmed, he says. "The limiting definition of pregnancy, 'being with child,' can easily be expanded to incorporate the word's richer nuances, 'filled or abounding'; 'fertile, rich, full of meaning or possibility'; 'highly significant'; 'teeming with ideas and imagination.' "

Both books offer utilitarian advice, and both counsel fathers about what their partners are experiencing during pregnancy. But the sections I found most interesting dealt with men's emotional response to pregnancy.

This response is no less complex than that of women's; expectant fathers feel everything from relief to denial, fear to frustration, anger to joy.

In fact, many men also experience physical symptoms, known as the couvade syndrome -- from the French word meaning "to hatch," or sympathetic pregnancy. Among the symptoms, familiar to pregnant women: weight gain, nausea, mood swings, food cravings.

But men experiencing the couvade syndrome often undergo additional maladies, including headaches, toothaches, itching and cysts. In almost every case, the symptoms disappear after the birth of the child.

In ancient and many non-Western societies, couvade has been purposefully ritualized to keep fathers involved in pregnancy and childbirth -- or to celebrate the coming of life.

With or without couvade, most men ride a nine-month emotional roller-coaster. A surprising proportion of expectant men, 60 percent by one study, had fleeting or nagging and (usually) irrational fears that they were not the biological father. "These men may feel that they simply aren't capable of doing anything as incredible as creating life," according to Brott and Ash, "and that someone more potent must have done the job."

Jealousy is another unexpected emotion for many expectant dads. "My father, who was pacing the waiting room while my mother was in labor with me, suddenly got a gushing nosebleed," writes Brott. "Within seconds the delivery room was empty -- except for my mother -- as three nurses and two doctors raced out to take care of my poor, bleeding father. I'm sure he didn't do it on purpose, but for one brief moment during the delivery, Dad was the complete center of attention."

Men may also experience an intensified sense of reality (each moment becomes fuller) and mortality, as they realize how their life or death could shape the future of their child.

During these months, the roots of the family tree dig deeper. Expectant fathers often become fascinated with their family history. And they feel more attached to their immediate and distant relatives, even if they were not close before. On the other hand, men can also feel pushed aside by relatives who may view a father's involvement as cute or novel.

Especially in the last weeks of the pregnancy, many men begin to feel guilty about what they think they've put their partners through.

At this point, a man should guard against emotionally withdrawing from his partner. Heinowitz, a marriage and family counselor, says that rather than toughing it out or ignoring it, men should accept their ambivalence.

One way to do this is to recognize that their partner is probably filled with mixed feelings, too.

"Your partner can help by clarifying her needs and expectations ('I'd like some more time with you'), and by sharing her own concerns about becoming a parent ('I feel unsure of myself, too'). Most of all, you can help -- by talking about your changes with her and with friends."

And he wisely advises: "If your relationship with your father was good, you will be propelled through pregnancy by rich memories and eager anticipation. If your relationship was unsatisfactory, then you have some work to do.

"Pregnancy can be your wake-up call to resolve old issues and choose the type of father you want to be for your child."