Does Size Matter?

I was really surprised to see all that was harder later in life for low birth weight babies according to recently released study results. Even when variables like family income and genetics were controlled for, individuals born with low birth weight had lower incomes, poorer health and other diminished markers for quality of life as adults.

Even among siblings, low birth weight sibs had a tougher life than normal birth weight brothers and sisters.

Somehow birth weight seems too random a factor, except in cases of mental or physical disability, to correlate to health and income later in life. Don't we all know someone who was a five pound baby and is now a CEO, kickboxer or university president? I guess that's the difference between anecdotal and statistically significant data...