Sam and AlanWhen Britney Spears had her children 11 months apart, the gossip mongers had a field day, but other celebrities soon followed suit with their own back-to-back pregnancies.

Denise Richards and Charlie Sheen's little girls are 13 months apart, Matthew McConaughey and Camila Alves' babies are 18 months apart, and Gwen Stefani's boys, Zuma and Kingston, are about 2 years apart.

It seems all the rage to have babies close together and in my real life, I see it all the time -- mothers pushing double strollers or sliding down the slide with a toddler on their lap while an infant sleeps in their sling.

As someone who jumped on this trend (by accident) with babies spaced 18 months apart, it does beg the question: How close is too close?

A study in the Journal of the American Medical Association suggests that pregnancies less than 18 months apart leave the second pregnancy at risk for low birth weight and premature birth. The theory is that after the first pregnancy, a woman's body is too depleted to support the next one, so she goes into it at a deficit.

Other studies have said different things, some saying four years is the ideal spacing because it allows the most time alone with the parents and a healthy sense of self-esteem before a baby comes along and displaces the first, while others insist that one year is best because children never had time to get used to being alone.

I was eight years apart from my only sibling and I hated it. It was like being an only child with none of the perks and then a little baby came along who was much cuter than me and couldn't play Monopoly or Candy Land with me. No fun (I am still bitter).

I say it's all individual, dependent on the kids and dependent on the parents. My children adore one another and watching them play is one of the great joys of motherhood. When they're getting along and we're all snuggled in bed, I can't imagine having waited. Of course, this often comes on the heels of a day where they have hit each other, refused to walk, and had several accidents each. There are trade-offs to any distance and what is right for me may not be right for you.

So, how about you? What is your ideal baby spacing?