Experts have gathered more evidence on the link between low birth weight and youngsters reaching puberty at an early age.
Those who gain weight rapidly in their first two years of life are also more likely to reach puberty early, they said.
The latest study, from scientists at the Research Institute of Child Nutrition in Dortmund, Germany, followed 215 boys and girls from infancy to the age of 13.
They found those weighing between 2.5kg and 3kg at birth started their puberty growth spurt around seven months earlier than babies who were heavier.
Meanwhile, those who gained weight quickly in the first two years of life started their growth spurt four months earlier than those who had put on weight at a normal rate.
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Youngsters who had a combination of low birth weight and rapid weight gain were also at risk.
The experts also confirmed that girls who gained weight quickly as a baby tend to start their periods early.
The link between birth weight, weight gain and puberty held true regardless of whether a child became overweight.
The study was funded by the World Cancer Research Fund (WCRF) and was published in this month's American Journal of Clinical Nutrition.
Experts from the WCRF said going into puberty at an early age is linked to an increased risk of some cancers, including breast cancer and testicular cancer.
It has also been linked to other hormonal changes that could play a role in cancer's development.
Lead researcher, Professor Anja Kroke, said: 'More studies are now needed to identify the physiological mechanisms by which a low birth weight and rapid early weight gain affect the timing of the pubertal growth spurt.
'In addition, by gaining a better understanding of why early puberty increases cancer risk, we can improve our understanding of the causes of cancer, and therefore raises the possibility of preventing future cancer cases.'
Dr Panagiota Mitrou, science programme manager for the WCRF, said: 'This study has identified early life factors that increase a child's chances of starting puberty early, which shows that what happens to us even in the womb can influence risk factors for diseases much later in life.
'More research is needed before we can better understand the relevance of these findings for public health.
'Only then can start looking at whether we need to take steps to prevent low birth weight or monitor weight gain in infancy.
'Until more research is done, the best advice for parents is to give their children a healthy start in life by encouraging them to get into the habit of eating a healthy plant-based diet, be physically active and maintain a healthy weight.
'We estimate that doing these three things could prevent about a third of the most common cancers in the UK.'
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