Do first-born babies actually look more like their fathers?

According to an old notion, first-born children are genetically predisposed to appear more like their father. It was thought that this was done so that the father would accept the child as his and provide for and care for them. Another argument is that this would prevent him from eating the baby.

These theories obviously date way, way back, long before paternity tests existed (or cannibalism was frowned upon).

However, all new parents still find themselves asking, “Who does it look like?” when they first see their child. When someone meets a child for the first time, it’s frequently one of the first things they will notice.

But is there actually any truth to the theory at all? 

A 1995 study from the University of California sought to prove the theory by matching photos of 1-year-old children with pictures of their father. The study asked 122 participants to match photos of children at 1-year, 10-years and 20-years with photos of both their mothers and fathers. In infants, just under 50% guessed correctly for the fathers, as opposed to around 37% for the mothers. The success rates decreased significantly in 10-year-olds and rose slightly again in 20-year-olds.

A similar study in 2004 with a much larger sample size found that, in fact, most infants resemble both parents equally. 

In concluding the study, co-author and psychologist at the University of Padova in Italy Paola Bressan noted that to the best of her knowledge, “no study has either replicated or supported” the findings from the 1995 study that stated babies resemble their fathers.

But even though the science isn’t there to back up the theory, why do so many of us say it rings true, that firstborns do tend to look more like their father?

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Well, it’s probably because most of us are going off personal experience. But then the problem with that is, resemblances are highly subjective.

While one person may regard a baby as a “spitting image” of their mother or father, another may not detect any similarity at all. I mean, you’ve got to feel sorry for those babies and mothers back in the caveman days when that was all they had to go off!

We now know that children share 50% of their parent’s DNA, and there are dominant genes and recessive genes – which leaves rather a lot of room for variation.

That is to say, when a baby is conceived, it inherits one copy of each gene from each parent. Some traits may be dominant, meaning that the gene from one parent is expressed over the gene from the other parent, while other traits may be recessive, meaning that both parents must contribute the same gene for it to be expressed.

And then when you also have to take into account the fact that babies grow and change so much in the first year and every year after that. Some will start out with the spitting image of one parent, but as they grow they end up looking much more like the other. 

It also begs the question, is a father who is excited about having a child more likely to see himself in his baby than one who is nervous/anxious/not wanting it? Or will a striking resemblance shock even the most detached father into bonding with his child?

Ultimately, the combination of genes from both parents determines the unique appearance of the child. However, it’s important to note that while genetics plays a significant role in determining physical appearance, other factors such as nutrition, environment, and lifestyle can also have an impact.

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