Before a baby is born, it's only natural for parents to dream about what the child will look like.Truth is, the odds of them being right are very long. Look at the numbers. Experts estimate there are 60,000 to 100,000 genes in a baby's 46 chromosomes — 23 from the mother and 23 from the father. All the possible combinations add up to this: One pair of parents can produce 64 trillion different children. That's a lot of variation; some major, some minor, in things like hair color, the shape of eyes, height, everything — any physical trait you can think of. But most people aren't trying to answer the 64 trillion-dollar question.
There's a simple, popular theory that newborns tend to look like the dad. The thinking goes like this: The mother's identity is never in doubt; the father's can be less certain.
Now, put this reality in the context of hundreds of thousands of years of evolution, and the theory is that nature has determined fathers are more likely to care for a child if it looks like him. Voila: Nature, according to the theory, concocts those genes so that the baby will look like the father and increase the likelihood of tender, loving paternal care, ensuring the baby is provided for and lives.
Some research supports the theory. A 1995 study showed that people had an easier time matching photos of 1-year-old children with photos of the biological fathers than with photos of the mothers. A persuasive finding, but one that was described this way by psychologist Robert French at the National Center for Scientific Research in France: "It's a very sexy result, it's seductive, it's what evolutionary psychology would predict — and I think it's wrong."
Indeed, subsequent research has not replicated the 1995 finding. A 1999 study found that pictures of babies were matched equally with biological mothers and fathers. A 2004 experiment produced the same results. A couple of other studies concluded that babies looked more like the mothers than the fathers. And yet one more inquiry found that the more time a father spends with a baby, the more he thinks the baby looks like him. So much for a simple theory.
So where does this leave us? Well, with millions of cute babies and very few answers for the age-old question: Who do they look like?