I will assume you are talking about September 4th 2011. If so, that makes your estimated conception date December 11th 2010. However, this date could be out by a couple of days. It all depends on when you actually ovulated.
You got pregnant on the 25th of dec and ovulated on 31st-early January.
My due date is July 4th 2009 and we conceived October 11, 2008.
The answer is one/sixth of all couples that try to conceive are infertile.
That would make your estimated conception date December 30th 2010. This date might be off by a couple of days though. It also depends on the length of your menstrual cycles too.
novenber
1 sept 2009 and 2 sept 2009..
Probably September
March
September 17th 2009? Your conception date would be roughly December 26th 2008, give or take 5 days
Roughly March 6th
in march
April