The use of fertility drugs and/or invitro fertilization can increase the chances of becoming pregnant at a later age. Successful pregnancies facilitated by fertility treatment have been documented in women as old as 67. Studies since 2004 now show that mammals may continue to produce new eggs throughout their lives, rather than being born with a finite number as previously thought. Researchers at the Massachusetts General Hospital in Boston, US, say that if eggs are newly created each month in humans as well, all current theories about the aging of the female reproductive system will have to be overhauled, although at this time this is simply conjecture.