"This is part of the ongoing controversy about when a woman needs a mammogram," saysTIME's Christine Gormanabout a new study in the Journal of the National Cancer Institute. The study says that women who begin mammography before the age of 50 may not be increasing their chances of early detection of breast cancer. The American Cancer Institute -- a private, non-profit organization -- continues to recommend regular mammographic exams starting at age 40. "The problem for patients," saysTIME's Janice Castro, "is that if there is no scientific basis for early mammography, insurance companies will refuse to pay for it. Any woman who feels she needs it may have to pay for it out of her own pocket." A mammography costs up to $200.