New research from the University of Western Australia suggests that the daughters of women who give birth at the age 30 or older are more likely to experience symptoms of depression as young adults.

"This study suggests that older maternal age is associated with symptoms of depression, anxiety and stress in young adult females," Jessica Tearne, a doctoral student and lead author of the study, said in a statement.

For the study, researchers collected and analyzed data from the Western Australian Pregnancy Cohort (Raine) Study. From 1989 to 1991, pregnant women were recruited into this study, and provided psychological and demographic information. The resulting offspring then underwent psychological assessment at various ages over the next 23 years. They looked at self-reported levels of various symptoms of depression, anxiety and stress from 1,200 of the offspring at age 20 and compared them with the age of the mother and father at the time the children were born.

Researchers found that daughters of women who were30 to 34 when they gave birth had higher levels of stress and those whose mothers were over age 35 at the time of birth had significantly higher levels of stress, depression and anxiety compared with daughters whose mothers were under age 30.

Women who were under 20 years old when they gave birth did not have an effect on their offspring. Researchers found that the fathers' age at the time of birth also had no effect, and there was no effect found for sons.

"One hypothesis is difficulties may occur in the mother-daughter relationship because of a large age difference between the two," Tearne said. "It may be that a 30 or more year age difference between mother and daughter leads to a significant difference in the value systems that may cause tensions in the relationship, leading to stress, worry and sadness in the child, particularly during the transition to young adulthood."

Another possible explanation may be that the women who gave birth over age 30 would be in their 50s at the time their children were assessed and therefore more likely to be experiencing health problems associated with aging. Tearne said this could lead to higher levels of symptoms in the children.

"It is important to remember, too, that the study examined symptoms of distress, rather than clinical diagnosis," Monique Robinson, another author of the study, said in a statement. "It could be that the offspring of older mothers are at risk for a few more symptoms of depression, anxiety and stress, but that does not necessarily mean they will experience a diagnosable mental disorder."

The findings are detailed in the Journal of Abnormal Psychology.