Why only children are smarter

If you're trying to decide how many kids to have, you might want to consider these important factoids first.

A recent Personality and Social Psychology Bulletin study has shown that siblings are the key to health, wealth and happiness. The number of brothers and sisters you have can also determine your level of intelligence.

It found that the more siblings you have, the lower your IQ.

I knew it. Meet my siblings...

Pictured is a photo of my little brother Biagio on the left, then me, then my big sisters Anna and Marina. Let's call this photo Exhibit A.

THEY are the reason I'm not as intelligent as I wish I was. I'm the third youngest. I never even stood a chance. What were you thinking by having four kids, Mum? WHAT WERE YOU THINKING?

I jest.

Still, I think there's something to this study.

My oldest sister Marina is the most academically gifted and just keeps on studying and going to seminars. It's exhausting just to listen to. Then, my sister Anna is the most spiritually aware out of all of us. She's a seeker, a searcher, a traveler. She's also the most financially savvy. My brother is extraordinarily sharp and smart and has a fabulous career in IT.

Then there's me.

I'm a bit of a floater. I drift around my career trying to find my place and radio and writing ended up being my careers of choice so I can share and discuss my confusion.

So let's call this article Exhibit B, shall we?

Seriously, there's a case for and against having too many siblings. Let's go through them so you can make an informed decision.

The case for lots of siblings

* Men with lots of brothers are more fertile;

* Men with brothers are more likely to have sons. Cute!

* You'll share health problems due to genetic factors and learned lifestyle issues, so you can all share medications and give each other advice;

* The oldest in the family is less likely to suffer from eczema, allergies and hay fever;

* They are thinner;

* The younger siblings are more relaxed and creative;

The case against lots of siblings

* Children with few siblings live longer;

* They are taller;

* Those with more siblings die younger due to limited resources;

* The more kids you have, the lower their IQ, especially the younger ones;

* A woman's risk of a heart attack goes up by 25 per cent after the death of a sibling, and 15 per cent for a man. Sad! It's called the bereavement trigger;

* Children with less siblings have higher self-esteem due to less fights.

So there you go. Weigh it up carefully. The bottom line is that if you have lots of kids they'll be thin but suffer from low-self esteem, and be short and dumb and die younger, but won't have hay fever. If you have less kids they'll be obese but with high-self esteem and live longer, and be tall, and have eczema.

How did you decide how many kids to have?

I never thought I'd settle for a conventional life. I was always such a rebel...and now here I am, a wife, a mother (and loving it!). I also dabbled in radio and traffic reporting for, oh, two decades. Now I'm a staff writer at iVillage Australia. Find me on Facebook and on Twitter.