As more National Guard and reserve units are deployed for the war in Iraq - 216,800 have been called to active duty so far - more noncustodial parents find themselves in the same circumstances that Wetzel did. If they fall behind in child-support payments because of reduced wages, they could incur penalties when they return home.

"The issue is very real," says Cmdr. James Semerad, a family readiness officer in the naval reserves at Fort Belvoir, Va. A month ago, he gave a presentation on child support to his unit, telling them, "Your [child-support] obligations don't go away."

Similar challenges confront another group of noncustodial parents these days - those who are unemployed. As downsizing continues, some laid-off workers, living on modest unemployment checks or savings, are unable to keep up court-ordered payments.

Now some family advocates are making quiet pleas for realism and reform for both groups of parents.

"People can't pay what they don't make," says Dianna Thompson, executive director of the American Coalition for Fathers and Children. "We're not saying that servicemen should not support their kids. But we can't ask people to serve their country and not give them some protection. And when people get laid off through no fault of their own, we can't punish them by giving them unrealistic child-support orders."

In 2000, nearly 14 million custodial parents cared for 22 million children under the age of 21. Among these custodial parents, 85 percent are women and 15 percent men. In the middle are children whose need for food, clothes, and haircuts does not diminish when a noncustodial parent goes to war or loses a job.

Yet challenges exist in determining fairness and in overcoming bureaucratic obstacles. Some reservists receive only a few days' notice to report for duty. For them it is impossible to get a court hearing to request a reduction in child support. Other reservists mistakenly assume they can work out the details when they return.

"I receive calls from soldiers all the time, and they're not being informed," says Jeffrey Leving, a fathers'-rights attorney in Chicago. "A lot of them are going to be coming back from Iraq and face court proceedings." After Desert Storm, many men who contacted him had large child-support arrearages they could not afford to pay.

Legal experts trace part of the challenge to measures put in place over the years to protect custodial parents and children from constant changes in support or lapses in payment. Federal law, they note, prohibits courts from retroactively modifying or forgiving child-support debts. In 1999, 46 percent of custodial mothers - 2.8 million women - who were owed child support collected the full amount, according to the Census Bureau. One-quarter of those due support received nothing.

The Soldiers' and Sailors' Civil Relief Act, which limits annual interest rates on credit-card debts, mortgages, and car loans to 6 percent during military service, does not cover child-support arrearages. And some states limit how often parents can request changes in support.

These measures, says Mark Rogers of Atlanta, an economist and expert witness on child support, were enacted in the "best interest of the child," but "without regard for economic common sense and an overall sense of fairness."

If a child's parents were still married, Mr. Rogers explains, the entire family would be expected to share the financial strain of a reduced income by cutting expenses and borrowing money, rather than having that responsibility fall on one parent. Fairness, as he sees it, means allowing noncustodial parents to pay child support that reflects their actual salary in bad times and good.

For Eddie Wright of Dunwoody, Ga., the divorced father of a teenage daughter, these are not good times. Last year he was unemployed for four months. He took a job with a fiber-optic cable company, but four months later, in December, that firm cut back, and he was out of work again.

Mr. Wright's divorce decree states that if he ever became unemployed, his $1,210 monthly child-support payment would drop to $833. But even that amount takes 73 percent of his $1,136 unemployment check before taxes. After taxes, he is left with $205 a month.

"If I wasn't fortunate enough to have an inheritance that I received after my divorce, I would be in jail for not paying child support," Wright says. "I used my entire savings the last time I was unemployed."

In February, he went to court asking for a modification. But under Georgia law, because he had filed for an earlier modification, he cannot make another request for two years.

"With the economy being in such disarray, it's unfortunate that people can't file for a modification when they become unemployed," he says, adding that he has never been delinquent or late in paying. He is taking his case to the Georgia Supreme Court.

Robert Thuotte, a Boston attorney specializing in family law, advises those who have lost their job or are being called up for military service to find out how long their employers will provide compensation. Some companies pay the difference between civilian and military pay.

Reservists and unemployed parents should also try to negotiate in good faith with the person to whom they pay child support, he adds, by explaining the circumstances and working out an agreement for the time away. "The noncustodial parent should also file a complaint for modification in probate and family court as soon as possible." That can be done by mail.

Mr. Thuotte recommends hiring a lawyer. But that is often not an option for those whose resources are already strained. Wetzel, who expects to be called for another tour of active duty "any second now," says he cannot afford an attorney anymore. His net pay as a nurse is $423 every two weeks, after child support and $50 for a college fund for his children are taken out.

Rogers takes a different approach. He calls for "expedited procedures" so those who pay child support do not need to hire legal representation to get payments reduced if income drops.

When Christopher Nye, a computer programmer and Army reservist in Kentucky, was put on alert after Sept. 11, he asked his state child-support agency what his support obligations would be if he were called up. Although that call-up never came, he was dismayed by the time lag involved in getting a downward modification - sometimes several months. "The system is slow," he says. "Something has to be done."

So far, Missouri is the only state to do something. At the time of the first Gulf War, lawmakers passed a bill expediting adjustments of support for reservists called up for active duty if their income changes.

The Minnesota legislature recently introduced a similar bill.

Whether problems with child support stem from corporate layoffs or military call-ups, Laura O'Quinn, president of Parents 4 Child Support Enforcement in Sulphur, La., urges both parents to be understanding. "These circumstances require people to use a little common courtesy and common sense," she says.

Three weeks ago, Wetzel submitted another request to family court to modify his child support. "We'll see what happens," he says. Whatever the outcome of his case, he hopes for larger changes in policies and procedures. "It's an antiquated system," he says. "It definitely needs to be looked at."