Henry Higgins' lament, "A Hymn to Him" from "My Fair Lady" that one is tempted to hum while checking the new styles for fall by American and European designers. Why can't a woman be more like a man? The colors are right out of a man's tailored clothing department; the patterns are herringbones, tweeds and foulards, equally elegant and appropriate for men and women. k page 41 Women, from page 13 The clothes themselves are neatly tailored. The proportions, too, are mannish and -- most important -- oversized.

The idea of a woman in man's clothing is hardly new. Coco Chanel found it extremely sexy when her elegant French (women) clients dressed in trousers and blazers. "Annie Hall" introduced the stylishness of men's hats and ties and a Chaplinesque look. Elements of that style are still around. And without help from any designer, women forever have found men's shirts and sweaters, even pajamas, more comfortable than their own.

The appeal of men's clothes is simple -- quite literally. A few uncontrived parts worn together add up to an untricky, modern way of getting dressed. And for Washington, the mannish but soft look is a welcome and essential alternative to the confining, stiff "dress-for-success" suit, complete with a floppy bow at the neck.

DESIGNERS STARTED to fiddle with a menswear look when it became apparent that the nostalgic look -- narrow skirts, dresses with bustles and skirts with trains -- were not going to be a big hit with their customers. Preppie styles surfaced but were passed over as too familiar and dull, and the Japanese designers' creations, while admired for their simplicity, free-form shapes and inventive fabrics, produced few faithful followers.

There was little question that there was a need for a change. With so many women working, a simpler formula for dressing was necessary. And the man's suit, with its constant, neat look and unrestricted fit, seemed a worthy alternative. Besides, designers recognized that women were ripe for a return to pants. After several seasons of soft, supple fabrics, crisp tailoring was a welcome change.

But it's not just on the designer drawing boards that men's and women's style's have overlapped. The blending is going on everywhere. The lives of young men and women are often so closely interrelated that a woman staying over at her boyfriend's house finds it easy to wear his clothes, including his shorts and socks -- even underwear. (Calvin Klein and underwear manufacturers capitalized on such gender blending.) And in pop music, a certain sexlessness characterizes the top crop, including Boy George, Michael Jackson, The Eurythmics and now Prince.

THE FIRST HINT that the menswear look was infiltrating the fashion collections surfaced more than a year ago when designers in Milan showed most of their fall clothes accessorized with men's hats. Then kids began decorating their look with ties, loosely knotted and slightly askew. This look was soon coopted on the runway as well. Last winter a black tie invitation meant the woman as well as the man might show up in a tuxedo.

Now the menswear look is touching everything. Men's cardigan sweaters and vests show up in cashmere and wool for women and men. The oversized tweed coats that girls were resurrecting from thrift bins have been revived in deep, rich English tweeds. The classic boy coat, easy and oversized, is touted as the most popular coat for women, and a favorite for men, too.

And while the obvious man's hat and tie have been discarded as trite expression for women to wear to achieve a menswear look, other accessories such as the paisley muffler, the crocodile belt, the robe or smoking jacket, the subtly patterned sock, and tie oxford shoes add new dimensions.

Even women's hairstyles have adopted an androgynous look. Models who showed up for collections with short hair often found a hairdresser with an electric razor ready to "buzz" the back of their necks to give, at least from the rear, the look of the crew cut. Just as men have invaded the once "for-women-only" beauty salons, many young women, in New York at least, are going to barbers to get their hair done.

But no one has to wear trousers or men's shoes or stand in line at the local barber shop. There are lots of alternatives, for example, the mixed message. Try wearing a man-tailored jacket over a soft dress -- possibly one in a menswear pattern or with a sarong skirt. The addition of a satin blouse, a brilliant color, a generous earring or pin will not only individualize the menswear style but soften the masculine edge as well.

Just because a woman dresses with all the comfort and ease of a man doesn't mean she has to look like a man.