Being without a father when girls are young can bring on early puberty, according to a Canterbury University researcher.
PhD candidate Jacqueline Tither compared 68 pairs of sisters from father-absent homes with 93 pairs of sisters from father-present homes in New Zealand.
The sisters in each pair were full biological siblings who were at least two years apart in age and, in the father-absent families, the biological parents had split up prior to the younger sister getting her first period.
She found that common processes such as separation, divorce and departure of the father from the home could substantially change the age at which girls entered puberty.
Ms Tither's findings, which will be published in this month's Developmental Psychology Journal, back up previous research into early puberty.
However, Ms Tither's research used a unique within-family design to control for the possibility that pre-existing factors such as genetic and socio-economic differences between father-present and father-absent families accounted for the link between father absence and early puberty for girls.
Her study found younger sisters in father-absent homes started their periods significantly earlier than their older sisters. This was not the case in father-present families.
The younger daughters of the most dysfunctional fathers were most likely to experience the earliest pubertal timing, Ms Tithers found.
Psycho-social stress was one possible explanation for this, she said.
Given that early puberty in girls is associated with a variety of health and psycho-social problems such as mood disorders, substance abuse, adolescent pregnancy, and a variety of cancers of the reproductive system, it was important that risk factors for early puberty were identified, Ms Tithers said.