Biologically speaking, a woman’s best time to conceive and bear children is from the time of her first period (for most girls between age 12 and 13) and age 24. After age 24 chances of birth defects and problem pregnancies begin to rise. At age 30, a woman has used or lost 90% of the eggs she will ever have and this is why women in their 30’s typically have a much more difficult time getting pregnant.