Father nose best! Dads can recognise their own children based on their body odour, study finds

From used nappies or dirty laundry, the smells of fatherhood aren’t always the most pleasant.

But now, a bizarre new German study has found that dads actually prefer the smell of their own children.

Researchers at Technical University of Dresden found that fathers not only rated their children as smelling better but could tell their scent apart from that of other kids. 

The scientists found that dads were able to successfully pick out the smell of clothes worn by their own children a third of the time.

However, perhaps unsurprisingly, the dads found their children’s odour significantly less pleasant as they hit puberty.

It has long been known that smells play an extremely important role in human relationships.

Chemicals in your sweat which determine your body odour communicate information about your immune system, health, and emotion.

Between parents, this smell-based connection is especially important as it helps to reinforce a loving relationship.

Studies have shown that the smell of our own children tends to be perceived as pleasant and activates parts of the brain associated with pleasure and reward.

For this new study, researchers recruited 56 fathers and 73 of their biological children to take part in the study.

The children were asked to shower using a non-scented body wash before bed and were given clean, unworn shirts to sleep in that night.

Dads found their own child 22 per cent more pleasant to smell on average but, as these graphs show, that preference drops off sharply as their child reaches puberty. This effect is especially pronounced in daughters (left)

In the morning, the parents collected the shirts and sent them back to the researchers who used them to create body odour samples.

Each of the fathers was then asked to rank the smells according to pleasantness, sweetness, intensity, attractiveness, and how much they wanted to smell it again.

Finally, the dads were asked to identify which of the odour samples belonged to their child.

The researchers found that dads were able to recognise their child’s odour more accurately when they were younger – guessing correctly 37 per cent of the time for infants and 33 per cent of the time for prepubescent children.

That might seem fairly low, but it is significantly higher than the 17 per cent success rate that would be expected if the dads were guessing at random.

Dads were able to recognise their child by smell around 33 per cent of the time (blue segments show correct guesses) across all ages except for at the start of puberty

In the paper, published in Physiology & Behavior, the researchers write: ‘Similar to mothers, they [fathers] were able to recognize their own child’s body odor across the developmental span, with exception of early puberty.’

The researchers also measured the similarity of proteins in the father-child pairs’ immune systems which influence the composition of sweat.

However, they did not find any correlation between immune system similarity and dads ability to recognise their children by smell.

Dads also rated their own children’s smell as significantly more pleasant than the smell of other children.

On average the children rated their own child as smelling 22.8 per cent more pleasant than other children.

Scientists believe that the smell of a parent’s own child activates parts of the brain associated with pleasure and reward, helping to promote a loving relationship (stock image) 

The researchers argue that it is likely that the enjoyable feelings associated with the smell of their own child play an important role in how they were able to recognise their offspring.

Additionally, the perceived pleasantness of a baby’s smell has been linked with positive feelings that help promote bonding between parents and children.

The smell of our own children has also been shown to reduce feelings of stress in parents.

However, just like the ability to distinguish their offspring’s odour, this preference all but vanished when the children hit puberty, especially among daughters. 

The researchers believe that this may be an evolutionary ‘barrier’ against incest between fathers and daughters.

The researchers show that the preference dads had for their own child (blue bar) compared to other children (other coloured bars) drops off at puberty (far right graph) as a barrier against incest 

The researchers write: ‘The decline was associated with higher pubertal stages in daughters only, which supports the hypothesis of odour-mediated incest prevention in opposite-sex parent-child dyads.’

The researchers note that there is a similar effect between mothers and their sons, supporting the idea that body odour may serve as an incest barrier.

However, they also point out that hormonal changes during puberty could also be affecting how parents perceive their children’s smell so the reaction may not be linked to sexual attraction.