AS those classic mother-in-law jokes would suggest, dealing with the family you marry into can be hard work.
But research shows that we are actually more likely to have rows with our own family than the in-laws.
However, there is a catch. After couples have children the in-laws, now grandparents, feel more like family. And that sets the scene for them to join in all our family rows.
The study was carried out by the University of Turku in Finland and published in the journal Evolutionary Psychological Science. The researchers explained the potential for conflict when babies come along and in-laws lives' become closer entwined.
The shared reproductive interest ... created through a grandchild among kin lineages provides new reasons for grandparents to influence and interfere in the lives of other family members,' they said. Researchers suggested there may be a kinship penalty', or a drawback to a familial relationship, which makes us more likely to argue with our in-laws as we come to feel more closely related to them.
Lead author Mirkka Danielsbacka said: Daughters-in-law were more likely to report conflicts when their mother- in-law provided more grandchild care. This indicates that the increase in conflicts between in-laws is related to grandchild care.'
© Daily Mail