Daddy's girl

2019-03-07 07:15:18

By Alison Motluk GIRLS who have a good relationship with their father hit puberty later than those who don’t get on so well with dad, say researchers in the US and New Zealand. Although genes and factors such as diet and exercise are known to affect the timing of puberty, little is known about social influences. So Bruce Ellis of the University of Canterbury in New Zealand and his colleagues at Vanderbilt University in Nashville, Tennessee, studied 173 girls and their families in three towns in Tennessee and Indiana. The families were first interviewed eight years ago, before the girls entered kindergarten at the age of 5, and the girls have answered detailed questionnaires each year since then. At the start of the study, the researchers conducted two interviews of least two hours each in the girls’ own homes. The interviewers also watched the families during a meal, for instance, to assess how the parents’ interacted with each other and with their daughters and find out if there was a lot of encouragement and affectionate contact or discipline and harsh words. As the girls grew older, their annual questionnaires asked about the onset of puberty—if they had any pubic hair, if their breasts were starting to show or if they had had their first period. Most girls had had a period by age 13, says Ellis, but there was a great deal of variation. The researchers found a striking association between how well the girls got on with their fathers when they were little and how old they were when they entered puberty. The interaction between the girls and their fathers seemed to have a far more significant effect than the girls’ relationship with their mothers. Girls from families where there was no father, or where the father was abusive and disruptive, tended to develop early compared to girls whose fathers had been actively involved in raising them (Journal of Personality and Social Psychology, vol 77, p 387). “A father’s investment is important,” says Ellis. “It’s not only behavioural, it’s physiological.” Ellis suspects that paternal investment early in life gives girls physiological cues about what kind of reproductive strategy to pursue. “Long ago, it might have benefited girls to be early reproducers in response to low investment from their fathers,