Some of the stories about preexisting conditions and health insurance border on the absurd. In one recent case, a 4-month-old boy in Colorado was denied coverage because, at 17 pounds, the insurance company deemed him too fat. The Huffington Post reported this month that a Florida woman was rejected because she took anti-AIDS drugs after being raped, raising questions among insurers about whether she had HIV. And documents uncovered a few years ago by Consumer Watchdog detailed the underwriting practices of some large California insurers, which included automatically denying coverage to anyone with acne, asthma or attention deficit disorder, among other conditions, as well as expectant fathers and construction workers.

WASHINGTON, D.C. — Kelsey Jessup, 26, is a model of healthful living. The Palo Alto native runs five days a week, practices yoga and stays away from red meat. But none of that mattered when Jessup recently applied for health insurance. Because she had knee surgery to repair a high school soccer injury and went to the emergency room after fainting a few years ago, she was denied coverage by multiple insurers.

Ronald Sturm, 62, of San Jose is diabetic but has managed his condition for five years with regular insulin shots and by eating right. Otherwise he's in good shape, he says, pointing to his part-time job as a referee running up and down high school gymnasiums. But Sturm, too, can't get coverage; he pays out of pocket for doctor visits and medications and prays nothing major happens to him before he qualifies for Medicare at age 65.

"If I have a serious illness or get hit by a softball and have to go the ER," he said, "I'm in trouble."

The fear of going without health insurance and the frustration of not being able to do anything about it because of a preexisting condition is shared by millions of Americans who have tried unsuccessfully to buy insurance on their own — or worry about someday having to do so.

With rising unemployment and fast-rising health care costs eroding the security of employer-provided medical benefits, those concerns are fueling Congress' push for sweeping new regulations of private health insurers.

While much of the health care debate has focused on whether or not to create a so-called public option, or government-run health plan, the most fundamental change that Congress is considering may be its move to outlaw insurers' policy of seeking the healthiest patients and weeding out those most likely to need medical care, a practice known as medical underwriting.

"For people buying insurance on their own, it would be a completely different" experience, said Gary Claxton, a vice president at the Kaiser Family Foundation, a nonprofit health care research foundation. "They'd have a menu of good benefits to shop for and buy, and insurers couldn't turn you down for a preexisting condition. That just doesn't happen much now."

Some of the stories about preexisting conditions and health insurance border on the absurd. In one recent case, a 4-month-old boy in Colorado was denied coverage because, at 17 pounds, the insurance company deemed him too fat. The Huffington Post reported this month that a Florida woman was rejected because she took anti-AIDS drugs after being raped, raising questions among insurers about whether she had HIV. And documents uncovered a few years ago by Consumer Watchdog detailed the underwriting practices of some large California insurers, which included automatically denying coverage to anyone with acne, asthma or attention deficit disorder, among other conditions, as well as expectant fathers and construction workers.

Short of those extremes are millions of other cases in which people with medical conditions, serious and minor, have found themselves at the mercy of private insurers because they don't have group coverage through a job. Plans provided by large employers do not discriminate against those with preexisting conditions, as their higher health care costs are offset by those of healthier employees.

When the Mercury News recently asked readers to share their experiences with the health care system, time and again they wrote of being denied insurance for reasons beyond their control.

Trish Curren, a 32-year-old mother of two from Santa Clara, applied for insurance but was turned away repeatedly because she previously had been diagnosed with gallstone pancreatitis and irritable bowel syndrome. She went uninsured for 18 months but later managed to get coverage from the department store where she works. But the bare-bones plan carries a $4,000 deductible, which she can't afford on her minimum wage salary.

Lately, when she's particularly stressed, Curren's face has gone numb and she feels heaviness in her chest — symptoms that she fears could signal a heart condition. But she won't go to the doctor.

"It does worry me. I have two young kids," she said. "I'm trying to manage it the best I can on my own."

Insurance company representatives say their underwriting practices are driven by economic necessity. "Insurance doesn't work if only the people who are likely to have expensive health care costs buy the insurance," said Patrick Johnston, president and CEO of the California Association of Health Plans.

To that end, the health reform proposals pending in Congress envision a grand trade-off. Insurers would have to accept all comers, regardless of health condition — only a person's age, geographic location, family size and whether they smoke could be used to determine premiums.

In exchange, all Americans would be required to buy insurance, in many cases with the help of government subsidies, depending on their income. The so-called individual mandate could deliver tens of millions of new customers to insurance companies, including many young and healthy people who now forgo coverage.

The insurance industry recently has balked at the deal, worried that it will end up with the short end of the stick. Specifically, insurers are concerned that the subsidies to help people afford insurance and the penalties for not complying with the individual mandate are not adequate.

Those who can't get insurance now because of a preexisting condition say something has to change.

Sturm, who owns two carpet-cleaning franchises in addition to his work as a referee, is paying for his own diabetes medication and grateful to his doctor of 30 years for giving him a cut rate on office visits. The San Jose resident has been uninsured for four years, ever since he missed a premium payment when he traveled to Ohio for his mother's funeral, prompting his insurance company to cancel his plan.

Since then, he's tried repeatedly to get insurance on his own, to no avail. "I'm a diabetic on insulin," he said, "so they want nothing to do with me."

As she pursues a career as a musician and songwriter, Jessup is making ends meet as a waitress, a job that does not offer health benefits. The UCLA graduate, who now lives in Marina del Rey, said the reality of her situation crystallized recently when a friend who also lacks insurance broke her arm in a boating accident. The resulting hospital bill left her $20,000 in debt.

Jessup said she never imagined she'd be uninsured.

"The thing that's so infuriating to me is I'm one of the healthiest people I know," she said. "I was taught to be proactive about my health and now I feel like I'm being punished for it. It's like if you went to the doctor, they won't insure you. That's crazy."

Contact Mike Zapler at 202-662-8921 or  [email protected].