This article by MP Dunleavey is posted on MSN Money.  It made me stop and think.

 I’ve been a SAHM for 9 years.  I have no degree.  I have no career, aside from mothering.  How much will this time with my children cost me in terms of what I could have been earning for the last nine years? 

In the future, I may have to work harder or longer to be financially secure in my old age, but the years of being home with my children are priceless.