Michael argues that it was different for Deb because she was only seventeen when she had him - which was either in March (2.13) or November (1.11) 1970 -, as opposed to Mel in her thirties and with endometriosis; so she would have been 47 when the series started, making her year of birth 1953. Vic's year of birth varies between 1952 on his Babylon membership card and 1951 on his headstone, but he was always made out to be the younger one when it came up. Who knows?