More than 7 million people in this country want to have a baby but cannot without some medical intervention. But infertility treatment is very expensive — one course of in vitro fertilization (search) can cost more than $12,000.

Across the country, states have been addressing the problem by passing laws mandating that insurance companies offer some form of coverage for infertility treatments (search). But many of the laws include age limits, cutting off fertility treatments for women over a certain age, and adding a new twist to the debate over how old is too old to become a mother.

The newest front in this battle is Connecticut, which this month became the 15th state to mandate insurance coverage for fertility treatments. Connecticut, however, imposed an age limit of 39 — several years younger than those imposed by neighboring New York and New Jersey (44 and 46, respectively), and much too young for Connecticut's potential mothers who are incensed by the age cap.

"We feel insurance should cover it," said Teresa Le Ruo, a 42-year-old Connecticut resident hoping to conceive through in vitro fertilization. "They cover elective terminations of pregnancies. I don't see why they can't cover my in vitro fertilization," she said.

Le Ruo and her husband, Jim, adopted a baby last year, only to have his birth mother take him back. Le Ruo's doctor has now recommended IVF. Le Ruo said that age does not factor into insurance coverage of other conditions.

"What are they going to tell a woman with breast cancer (search)? 'Oh, I'm sorry, your stats for your age aren't very good, so we're not going to treat you?"

But how old is too old? Though Le Ruo described New Jersey and New York's age limits as reasonable, others may disagree. In the past decade, the number of women over 40 having babies has risen by 58 percent, but some insurers say the success rate of infertility treatments for women in their 40s is not high enough to warrant insuring such an expensive procedure.

That cost, they say, is passed on to everyone.

"For every 1 percent that health care benefits rise, several hundred thousand people across the nation loose their coverage, become uninsured," said Susan Pisano, a spokeswoman for Americas Health Insurance Plans.

Still, the trend does appear to be moving toward more states mandating some kind of coverage. Pennsylvania, California, Florida and New Hampshire are all considering it.

Click on the video box at the top of this story to see a report by FOX News' Alisyn Camerota.