THEY WERE both selling shoes in Gimbels when they met in 1969. But by the time Michael and Loretta O'Brien's divorce case was settled by the New York Court of Appeals last week, their economic circumstances had changed considerably, and in different ways.

Mrs. O'Brien, claiming that it was her salary and support that put her husband through college, postgraduate courses, medical school and internship, convinced the court that his medical license is an asset of the marriage that can be valued and divided between the partners at the time of divorce. It is the first such ruling in the country on a professional license as property.

Family courts are awarding far less alimony than in past years. Even in cases where women in long- term marriages had not worked outside the home, support payments are often temporary, designed to provide some help only until the women can support themselves. So the division of property that accompanies divorce becomes more important, especially to women for whom it is often the only monetary compensation after years of marriage.

Most states now look at assets that have been acquired or have increased in value during the marriage -- real estate, bank accounts, businesses, investments -- and divide them "equitably" between the parting spouses. The division would take into account such factors as the duration of the marriage and the contributions of both partners.

Dr. O'Brien left his wife to marry someone else only three months after receiving his medical license, so he did not, at that time, have an established practice, the value of which could be determined and divided. Mrs. O'Brien however, claimed that the license itself was an asset, one which she had helped earn, and that she was entitled to part of its value. Everyone agreed that she ought to be compensated for putting her husband through school and supporting him for many years -- he offered $25,000 -- but she has now won a great deal more. A lower court found that the license was worth $475,000, and awarded Mrs. O'Brien 40 percent.

Today's young woman is just as likely to be working her own way through medical school as paying a husband's tuition. And many a working man is sending his wife to graduate or professional school. Society changes, and those changes are dramatically reflected in family court cases. The New York decision will surely be cited in litigation all over the country, and many women who made critical choices involving family and career before the feminist revolution will benefit.