sentences:  Scientific interest in paternal age effects is relevant because the average paternal age increased in countries such as the United Kingdom, Australia and Germany, and because birth rates for fathers aged 30–54 years have risen between 1980 and 2006 in the United States.Possible reasons for the increases in average paternal age include increasing life expectancy and increasing rates of divorce and remarriage.Despite recent increases in average paternal age, however, the oldest father documented in the medical literature was born in 1840