Yes there is genetic variation and some younger siblings may be taller than the first, but the majority are not as tall as the first born. There can be many reasons for this, but most likely it is the health and nutritional status of the mother declines and depletes with every pregnancy.

Youngest children are also often described as spoiled, willing to take unnecessary risks, and less intelligent than their oldest siblings. As a result, youngest children are believed to be unafraid to do risky things. They might not see consequences as clearly as children who were born before them.

While they might not admit it to their kids, 23 percent of parents favor one child, and chances are, it’s the baby, a new survey has found. Of the parents who copped to having a preference, more than half said it was for their youngest kid, according to the 1,000-person poll by British parenting site Mumsnet.

A new study by researchers at the Universities of Houston, New South Wales and Sheffield have revealed that older siblings are smarter than younger ones – and even revealed why. Scientists found that the lower IQ in younger siblings could be down to differences in parental attention.

Oldest children are the smartest, research shows Research published in the Journal of Human Resources found that firstborn children outperform their younger siblings on cognitive tests starting from infancy — they are better set up for academic and intellectual success thanks to the type of parenting they experience.

According to a wealth of scientific studies, the ‘babies’ of the family are more likely to be slimmer, healthier and live longer than their elder brothers or sisters. On average, older sisters were 1 lb 4oz bigger. The same pattern has been found in men and the reason, scientists admit, is a mystery.

It’s not difficult to see how firstborns can become so tightly wound: new to their roles as Mom and Dad, first-time parents can be overprotective and tentative while at the same time strict and demanding, says Leman. This can lead to “oldest child syndrome” and the conscientious desire to overachieve.

16 Signs You’re The Youngest Child

1. You know how to entertain yourself.
2. You are used to waiting your turn.
3. You’re often told you’re “mature” or seem older than you are.
4. You can easily fall asleep with the lights or TV on.
5. You started watching MTV and R-rated movies earlier than many of your peers.

Being the youngest child is the best because they get perks that the older sibling(s) didn’t have. They also get more attention from their parents when their older sibling(s) go to college. The youngest sibling is spoiled because they are the parent’s last “baby” in the house so they often get whatever they want.