Bree and Eric are both in their 40s. They have spent their early adult years focusing on their education and careers. Now that they are financially secure and successful, they want to have a baby. Bree and Eric should know that couples in their 40s have a percent infertility rate.

50 %

Explanation:

A woman has fixed number of eggs. With each menstrual cycle, one egg is released. By the time a woman reaches the age of early 40s, the egg count has reduced tremendously and the chances of a woman being fertile are very low.  

Along with women, men also develop some issues with their sperm count and speed.  

Thus the probability of a man and woman having baby is  50% at the age of 40.

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