If babies are being born heavier than in previous generations - and they are - is that a concern? The fact that the average weight of newborn infants in many countries is rising has been seen as a concern.

Infants in broadly healthy, non-deprived countries such as Britain, the USA, Belgium and Denmark also tend to become heavier during the fist six month than they should, according to World Health Organisation (WHO) growth standards.

A number of researchers have linked these heavier babies to maternal obesity, and increasing rates of gestational diabetes, which happens when mums-to-be have trouble regulating their blood glucose levels

But are such babies predisposed to obesity? New findings from a team led by Glasgow University, but also including academics in Finland and London, looking at data from similar studies over the last five decades, suggests the picture may be more complicated.

While data shows modern children growing faster than the WHO standard, that weight gain is not maintained consistently. Meanwhile peaks in growth are comparable to those in large scale studies over the last fifty years, including those carried out before the obesity crisis.

The authors of the study - published in Archives of Disease in Childhood - say: "the lack of variation by era argues against obesity being the explanation."

In fact, looking for patterns, the team noticed that changes in growth tallied rather better with rates of breastfeeding in different eras or to improvements in the quality of formula milk which increasingly mirrors the nutritional content of breastmilk.

What does this mean? For one thing, WHO measures may not be a great match for better off countries, although the organisation's standards are not wildly unrealistic.

But if the weight of infants peaks after a few months and then begins to drop off, concern about infant obesity may be misplaced. The real question might be about why weight gain in young children peaks again at the ages five and eight, bringing many into the obese category. Is school for instance a factor, with a drop off in physical activity coinciding with confinement to a classrom? Or does it coincide with the age when children begin to take on more of the dietary habits of their parents, good or bad?

We still have a child and adult obesity problem. But perhaps this paper suggests new mums and dads don't need to be quite so worked up about what happens in early childhood.