The contract is not illusory. Mrs. Whitehead was anxious to contract. This court finds that she had changed her mind, reneged on her promise, and now seeks to avoid her obligations.

SO READ a recent ruling by New Jersey's lowest court.

The contract in question happened to be about a tiny girl who now will go by the name Melissa. However Justice, in the person of Judge Harvey R. Sorkow, did not let such trivialities cloud the real issues of the Baby M case.

Mary Beth Whitehead signed an agreement stipulating that, in return for $10,000, she would permit herself to be impregnated by William Stern's sperm, carry the product of that union in her womb and then surrender the resulting child to Stern. Sorkow refused to see so straight forward an agreement obscured. He prohibited any discussion of the nature of the bond between mother and child and barred testimony about the legality of surrogate parenting.

He awarded custody to Stern, permitted Elizabeth Stern to adopt the baby on the spot and--keeping things tidy--denied the court-appointed guardian's recommendation that the natural mother retain some parental rights. A deal, Sorkow's ruling reminded those who may have forgotten the schoolyard-taunt of a kid who has taken advantage of another, is a deal.

THE DISPUTE surrounding Baby M involved profound issues of law, psychology and theology. Whitehead thought she had a product to sell, in this case an unfertilized human egg, and a service to offer, that of a mobile human incubator. Stern wanted what Whitehead could provide and agreed to a price. What went unaccounted for in the deal was Whitehead's joy at the baby's first kick, whatever sense of expectation surges together with a bout of morning sickness and the satisfaction of a mother holding her child in a delivery room.

The agreement Stern and Whitehead struck required her to experience such feelings--for a fee. But there are limits to what men and women can know about their own bodies or their own psyches, and they remain even when technology makes it possible for one woman to bear a child for another. No one can predict what feelings a particular pregnancy might inspire well enough to put a price on them.

Furthermore, the emotions Stern and Whitehead tried to barter were not really their own. Like love, hate or appreciation of beauty, motherhood is something an individual can experience but not package for sale. The experiences of pregnancy, though personal, are too fundamentally human to be mere private property. What Whitehead felt during the nine months she carried Melissa, whom she calls Sara, were emotions that are part of her humanity. What is not owned cannot be sold.

SORKOW MIGHT counter that he had something more important than the nature of the species' to protect: the welfare of one of the species' tiniest representatives. He argued as much when he called the affair a "routine custody case" that turned on "the best interests of the child."

The judge wrote that Whitehead was "manipulative, impulsive and exploitive...a woman without empathy." Stern and his physician wife, he reasoned, would make better parents; they could surely provide more advantages for the baby than Whitehead, a high school drop-out, and her garbage collector husband. The Sterns, he noted, might one day give Melissa music lessons.

Sorkow thought it less worthy of note that the Sterns misrepresented themselves to Whitehead. The couple appealed to Whitehead's sympathy by telling her they were unable to have or adopt a child. The contract Whitehead signed stated that Elizabeth Stern was infertile. She was not.

Elizabeth Stern diagnosed herself as having a mild case of multiple sclerosis. But the couple did not have a specialist confirm the diagnosis until late 1986, did not inquire whether the disease affected her ability to bear a healthy child, and did not seek to adopt a child. William Stern wanted a genetic link. Yet if Sorkow is to be believed, these facts reveal nothing about the Sterns' fitness to be parents.

In determining who would best mold the young girl into an adult, the judge did not grapple with any elements of human nature except those that can be clearly specified in a contract, assessed and sold. In such a context, his statement that he was influenced greatly by what he believed to be the Sterns' greater ability to explain the circumstances of Melissa's birth and upbringing makes sad sense.

The couple--far better than Whitehead, it is true--can tell Melissa how the affluent can use the less fortunate for their own ends. In the world Sorkow's decision would create, where motherhood is a commodity and feelings are reserved for those who can afford them, no knowledge would be more valuable.