When Metropolitan Opera star Frederica von Stade performs, her audience basks in the glory of a great mezzosoprano. Her talent appears uniquely personal: beginning somewhere around her diaphragm and ending in an outstretched arm. Her former husband, Peter Elkus, disagrees, saying that as her voice coach during their 17-year marriage, he helped her achieve stardom. Last week a New York appeals court backed him up, saying his contributions to his wife’s career must be compensated in a divorce settlement.

The price of celebrity has just gone up. Last week’s controversial decisions broke new ground in matrimonial law. They expand the definition of marital property to include personal accomplishments like fame or potential (rather than actual) earnings. In the von Stade case, the court found that stardom has a value, like a business or a car; it can be considered marital property and assigned a monetary amount. In the Gastineau decision, the judge was essentially second-guessing the old sack dancer, demanding that responsibility to family be placed above free choice of a career.

Presiding over divorce cases has never been an easy job. The celebrity decisions reflect the struggles courts are having trying to divide up rights to what’s become known as “new property.” According to New York appellate Judge Ernst Rosenberger, writing in the von Stade case, “Things of value acquired during marriage are marital property even though they may fall outside the scope of traditional property concepts … The property may be tangible or intangible.” Hence, pensions don’t belong just to workers, nor copyrights to writers nor professional degrees to those who’ve earned them. Instead, marriage has come to be seen in many state courts as a partnership that carries with it economic interests that outlive the marriage itself. This reflects the more complicated nature of society, the advent of the women’s movement and the accumulation of wealth in America. When there are no assets-or children-divorce is a simpler matter.

Last week’s rulings have effect only in New York, and it’s highly unlikely the von Stade decision will be copied around the country. Five years ago the state’s highest court ruled that a medical license, with its potential for higher earnings, was a marital asset if a spouse helped his or her mate attain it. Subsequent decisions gave the same status to law and accounting degrees. But most states have refused to follow those precedents. California, Massachusetts, Illinois and Michigan-and 22 other states-have chosen instead to award alimony or some other reimbursement rather than granting a share of the degree.

In Hollywood the issue of joint rights to a spouse’s success often comes up. Lawyers try to get their clients a portion of a divorced star’s earnings under a concept called “celebrity good will,” a vague asset to which they ask the court to ascribe a dollar amount. So far there is not a single case in which this has been awarded, though several cases have been settled out of court. (Also, a version has turned up as an “L.A. Law” plot device.) One recent settlement was in a suit by Bill Pentland, Roseanne Barr’s first husband, that sought a portion of the star’s future earnings. He claimed he supported Barr during her lean years, and therefore her later success belonged to both of them.

In Gastineau’s case, the issue was his past success. The decision didn’t require him to pull on his shoulder pads again, but it did conclude that by walking out on his lucrative contract, Gastineau had “wasted” a marital asset. “It’s an outrageous decision,” says Chicago divorce lawyer Joseph DeCanto. “Just because we marry, we haven’t surrendered every vestige of the right to make choices.” But New York divorce lawyer Eleanor Alter explains that the court simply thought Gastineau’s arbitrary rejection of football was not “reasonable or responsible.” “If you forget the income level,” she says, “the idea that an able-bodied man who is a father could refuse to work and choose to go off in the sunset with his girlfriend is simply odious.”

Fathers are often riding off into the sunset. According to the Census Bureau, nearly 9 million families have children with absent fathers. In 1985, the most recent year for which figures are available, 4.3 million mothers had child-support awards. But fully 1.1 million didn’t collect a penny, and another 1.1 million received only partial payment. Only 2.1 million women collected the full amount, and they tended to be women in higher income brackets. As important as the new property issues may be, the crisis in divorce courts is an old one: estranged parents not meeting their obligations.