Did it take you awhile to conceive him or did it happen quickly? If it happened quickly, I personally would start trying shortly after he turned 1 so in case it took a couple months to conceive the next one would be born around your first babies 2nd birthday, I think a 2 year age gap is perfect. If it was harder for you to conceive, I would start trying now. It took me over 2 years to conceive my son and I plan to start TTC again in Novemeber when my son is 10 months old. Their really is no specific spacing, this is just my preference, good luck with your decision.