Advanced parental age at conception and sex affects mitochondrial DNA copy number in human and fruit flies.

Aging is a multifactorial trait caused by early as well as late life circumstances. A society trend that parents deliberately delay having children is of concern to health professionals, e.g. since advanced parental age at conception increases disease risk profiles in offspring. We here aim to study if advanced parental age at conception affects mitochondria DNA content, a cross species biomarker of general health, in adult human twin offspring and in a model organism. We find no deteriorated mitochondria DNA content at advanced parental age at conception, but human mitochondria DNA content was higher in females than males, and the difference was two fold higher at advanced maternal age at conception. Similar parental age effects and sex-specific differences in mitochondria DNA content were found in Drosophila melanogaster. In addition, parental longevity in humans associates with both mitochondria DNA content and parental age at conception thus we carefully propose that a poorer disease risk profile from advanced parental age at conception might be surpassed by superior effects of parental successful late-life reproduction that associate with parental longevity.