I have two sons - 22 months between them, I knew I wanted more than one so just went ahead hoping for a two ish year gap. Things have been great between them - no jealousy and they are already playing together really well now the youngest is nearly 9 months old. The broody thing never goes, although the lack of sleep is a great contraceptive! It has been a big old juggling act though, dealing with terrible two tantrums and a hungry baby that needs feeding has been a challenge but in the long run I think a small gap is great. My eldest has also learnt that he has to wait for things if I am busy with his younger brother and is sharing really well. The toddler groups are great for both of them and without a big gap you can do lots of activities together. I would recommend it and I also think if you want more than one just get going and worry about it later!!