Considering a Third Child at 35: Risks, Rewards, and What to Consider

Question
Hi Doctor-I have 2 boys ages 4 and 5 and I would like one more child. I'm having trouble making a decision and hope you will give me some information. I just finished my masters and am now progressing in my career. I feel we are over the hard parts with our boys and they are so close in age that we are able to do activities with them now-canoeing, water parks -beach. I'm scared at age 35 if I should take a risk and have another one. I worry about genetic disorders and problems! I don't really have any history of Down's syndrome or problems in our family history but I am 35 and will be 36 in a month. Does getting pregnant again after being stable for a 4 year period with the hormone flux cause women increased harm in the long run for diseases.  Is there any risk or benefit-health wise to having a baby besides the obvious blessing of a child. Maybe you can help me. Thanks  

Answer
There is no problem with becoming pregnant after the age of 35 except for the possibility of chromosomal abnormalities. The risk of Down's syndrome at the age of 30 is 1:2700. At 35years of age, it is 1:350. At 40 it is 1:100. However, you can (and should) get an amniocentesis at 18 weeks gestation and if there are any problems you can decide what course to take. The obvious blessings of having a third child are evident and I'm sure your boys will adore having a baby sibling (especially if it turns out to be a girl). Good luck.