NEW YORK -- As a growing number of children and teenagers become overweight and obese, more are facing heavy decisions about their health.

At age 16 and nearly 300 pounds, Stephanie Villanueva was self-conscious about her weight. It wasn't just Stephanie -- her mom and dad were also obese, which suggests genetics as the problem, reported WNBC-TV in New York.

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"It was dangerous for me to be so big, because there's high blood pressure in my family and there's diabetes in my family," Stephanie Villanueva said.

But more than just genetics are at play, according to Stephanie's parents. The family loved to eat.

"When we go to restaurants now, it's amazing," said Aida Villanueva, Stephanie's mother. "We can all eat from one portion and still have food left over, whereas before when we would go in we would have salad, entree, dessert and a couple hours later, be ready to eat again."

The concern with obesity in children is that kids are now developing adult diseases.

"The problem is that we are starting to see complications in children that we never used to see. Type 2 diabetes was rare in children until the last 10 to 15 years," said Dr. Ileana Vargas of Columbia University Medical Center in New York.

Type 2 diabetes used to be called "adult onset diabetes" because it usually wasn't seen until middle age. Obese kids are also developing high blood pressure, high cholesterol and joint problems, and these problems only get worse as obese teens grow into obese adults.

Years of these health risks mean children are more likely to eventually suffer complications like heart attacks, strokes, sleep apnea and asthma.

Even though she tried, Stephanie wasn't able to lose weight through diets and exercise -- and neither were her parents.

Stephanie opted for gastric bypass surgery, where surgeons make the stomach much smaller and bypass much of the intestine. Both of her parents had it done and are losing weight, too.

Other surgeons, though, prefer something called laparoscopic gastric banding for teens, where an adjustable band is wrapped around the top of the stomach to make it harder to eat. It's reversible and less risky.

But for a teen, any surgery should be a last resort, experts say.

"Surgery is not a cure for obesity. Surgery provides a control mechanism," said Dr. Mitchell Roslin of Lenox Hill Hospital in New York.

But to make any weight-loss program work, whether its lifestyle changes or surgery, the key is the same: You still have to exercise and eat small, healthy portions.

"I have become so much more social and friendly, and I'm happy. Physically and healthwise, I'm so much more content than I was," Stephanie said.