How Old is Too Old?

I submitted a debate Hot Board suggestion to iVillage, and they've created it yesterday!

Do you think that a woman should always have the right to decide whether she's ready to face the challenges of motherhood, no matter how old she is?
Should doctors always assist women in becoming pregnant, regardless of their age? Or do you think doctors and society have the right to just say no because of the potential risks and costs? How old is really too old to become a mother?

http://messageboards.ivillage.com/iv-prhttooold/