Why would that be so? Think about what an egg is and what it does. Compare an egg to a sperm cell, which is essentially a DNA-filled ziplock bag with a tail. Its job is to deliver DNA to the egg and safely usher it inside. A good sperm cell contains normal DNA and has an effective way to gain entry into the egg. This process is so inefficient that nature sends millions of sperm cells out for each egg, to insure that one individual sperm cell gets the job done. Once the sperm has delivered the male DNA, however, the egg itself has to do the important work. It must provide an environment for the effective combining and replication of the now combined male and female DNA, and must split again and again in an equal fashion.

Looking For Good Eggs

A “good egg” has two functions: it must have good normal chromosomes and it must let those chromosomes combine with those from a sperm cell and subsequently divide in an efficient fashion. Eggs with abnormal chromosomes or eggs with cytoplasm (the non-DNA containing portion of the egg, in a simplified but not entirely accurate view) that cannot foster the effective distribution of chromosomes as it splits are the cause of the difficulty women experience as they age.

Unfortunately, egg quality is not easy to judge. Although egg quality declines as women get older, going by a woman’s age is not enough. Two women at the same age can have vastly different possibilities of conceiving on any given month. Differences seem particular wide in the 36-41 year old age group. And while we can easily look at sperm, look at its shape and watch it swim, we can directly view eggs only after they have been somehow removed from the ovaries in an unnatural way.