Paternity rates in the US 1993–2002: Analysis of birth rates by paternal age and race

Abstract

Many couples are waiting until later in life to have children due to social and economic issues. Much interest has been generated in the association between increasing paternal age and pregnancy outcomes. Evidence from both animal and human studies suggests that age-related changes in male germ cells may result from factors such as sex chromosomal non-disjunction, chromosomal translocation, environmental damage, genomic instability, and impaired apoptosis. These age-related changes may result in pregnancy loss or transmitted genetic disorders. In order to define the current trends, we studied the changing birth rates in the US over a 10 year period, in relation to the paternal age and race. Retrospective analysis of US population and birth rate data from the National Vital Statistics Reports, volume 48, No 3, National Center for Health Statistics. Birth rates were calculated by dividing total live birth by population in different decades of paternal age. Changing birth rates were compared in terms of paternal age and race. Between 1993 and 2002, the birth rate for all US men decreased for fathers aged 20–29, while it increased for fathers aged 30–39. For fathers aged 40 and above, the birth rate remained stable.(Graph 1) In terms of race, the birth rate for US White men decreased for fathers aged 20–29, while it increased for fathers aged 30–39. In contrast, the birth rate for US Black men remained stable for fathers aged 20–29, while it increased for fathers aged 30–39. Additionally, the birth rate for US Black men was overall higher than that for US White men for fathers aged 20–29. Finally, the birth rate for US Black men remained lower than that for US White men for fathers aged 30–39. (Graph 2) For the time interval studied (1993–2002), there was an increasing paternity rate in men aged 30–39, regardless of race. This trend is important, as evidence suggests that increasing paternal age may result in increased risk of pregnancy loss or transmission of genetic abnormalities to offspring.View Large Image Figure ViewerDownload Hi-res image Download (PPT)