Experts from Newcastle University looked at the records of nearly 4,500 women from all backgrounds and regions of the UK, and found several early life factors which seem to have an impact on the age at which girls give birth.
The paper, which is published today in Proceedings of the Royal Society B, shows that girls who are separated from their mothers for a period of time in their first five years of life are more likely to have their babies earlier.
But the effect goes away if the separation is longer than 24 months.
Dr Daniel Nettle, lead author of the study and reader in psychology at Newcastle University, said: “We found that where a girl was separated from her mother for between six and 24 months during the first five years, she gave birth to her own first child over two years earlier than a girl who has been in full contact with her mother for all her early childhood.
“Interestingly, where the separation from the mother is more permanent, i.e. more than 24 months, the effect goes away.
“The child whose mother has been away for 24 months or more is likely to have been adopted into a more stable family.
“This suggests that it is the security of attachment which has important effects on the developing child.”
The paper also found links between short duration of breast feeding, frequent family housing moves and lack of paternal involvement and girls giving birth at younger ages.
Dr Nettle said: “It is hard to show causality but we have controlled for various factors as much as we can and we believe these links are clear.
“Reproductive development is much better studied in women than men, so the next step will be to examine the men from the same cohort.”