Professor Tom Kirkwood of Newcastle University has come up with a new theory for why women live longer than men, the Daily Mail reports. Men are simply more biologically "disposable". The controversial study shows that the female body is better at carrying out routine maintenance and keeping the body's cells alive. The aging process is caused by tiny faults throughout our body. As faults build up, the length of our lives is determined by how quickly our body is able to carry out running repairs. As the cells miss opportunities to repair themselves, our bodies gradually degrade until we eventually die.