From the marketplace to the workplace, it is mothers who are still perceived as having that "special bond" with their children. This is compounded by advertising and the widely held expectation that it will be mothers who take parental leave.
But in a rapidly changing society, is there really any reason to assume that mothers are any more suited to take care of their children than fathers? Some will argue that a superior "maternal instinct" is part of a woman's biology. But do pregnancy, hormones or parenting experiences really create a stronger bond? Let's take a look at the scientific evidence.
Some scholars argue that the relationship between parents and children can begin before birth. They claim that such "antenatal bonding" – feeling connected to the unborn baby – is an important predictor of the infant-mother relationship. However, the actual evidence linking feelings about the baby during pregnancy with postnatal behaviour is inconsistent, so it's not clear how – or even if – such feelings influence later relationships.
But even if it is shown to be the case, another problem is that most of the research in this area has been conducted with mothers. We are now also starting to understand that fathers develop antenatal relationships too. It is also clear that not having the experience of pregnancy at all doesn't mean that later relationships are compromised – as those who have adopted a child or started a family through surrogacy arrangements know.
Fathers change too
Oxytocin, commonly heralded as the bonding hormone, is known to be released in large amounts during birth and breastfeeding to help regulate maternal bonding in mammals. However, less well known is that fathers experience rises in oxytocin equal to mothers as a result of interacting with their infants. There are, however, differences between mothers and fathers in the types of interaction that seems to produce these rises in oxytocin. For mothers, it is behaviours such as baby-talk, staring into the baby's eyes and affectionate touch. For fathers, playful touch and behaviour – such as moving their baby around or presenting objects – seem to produce the rise in oxytocin levels.
A huge problem when it comes to understanding the differences – and similarities – between fathers and mothers is that most research on bonding doesn't directly compare the two. This is likely to be because mothers still stay home with the child more often than fathers, and researchers might have difficulties finding enough households where fathers are in the role of a primary caregiver. So we don't really know whether fathers interacting with their babies differently to mothers is about their biological differences or about roles taken in relation to breadwinning and child rearing.
But how good are fathers at understanding their child's needs compared to mothers? One study examined the ability of mothers and fathers to identify the cries of their own infant from those of others, and found that this was directly linked to the amount of time the parent spent with the baby – rather than their sex. Other research has found that fathers' hormone levels seem to be affected by hearing infant cries and that hormone levels influence the way in which they respond to the cries.
We also know that while there are some subtle differences in the way that mothers and fathers show understanding of their infant's thoughts and motivation, the extent to which they do this is predictive of later security in the child's relationship with them.
So although more research is needed, the evidence so far suggests that the argument that biological mothers have a greater bond than other parents is difficult to substantiate. Because factors like antenatal bonding, hormones, experiences, and even our own childhoods all interact together to influence the bonds between a parent and child, it doesn't make a huge amount of sense to try to pin the strength of these relationships on sex differences.
What makes parent-child relationships work is complex, and we don't yet know all the answers, but being alert to the child's experience and understanding and responding to a child's needs in a sensitive manner seems a good place to start.
Explore further: Gender inequalities exist for fathers in the Swedish child health field