We decided to 'unofficially try to conceive' (as we called it ) #2 straight after having DS1 - he had taken 3 years (and many fertility treatments) to get him so we felt if it happened naturally then it was meant to be...and it was! I'd only had 3 AF's and hadn't really worked out a pattern between them and I had only just finished BF (within a month) - so we were pleasantly surprised when we discovered we were pregnant with DS2...they are 20months difference (conceived on DS1's 1st birthday ).