According to Official Guinness Records,
The record for the most generations born on the same day is four held by six families:-Ralph Bertram Williams (USA) was born on 4 July 1982 in Wilmington, North Carolina. His father, grandfather and in 1876, his great-grandfather were also born on 4 July.Veera Tuulia Tuijantyär Kivistö (Finland) who was born in 1997, shares her birthday of the 21 March with her mother (1967), her grandfather (1940) and great-grandfather (1903- 1978).Maureen Werner (USA) was born on 13 October 1998 and shares her birthday with her mother (1970), her grandfather (1938) and great-grandmother (1912).Jacob Camren Hildebrandt (USA) was born in 2001 and shares his birthday of the 23 August with his father (1966), his grandmother (1944) and great-grandmother (1919).Mion Masuda (Japan) was born in 2005 and shares his birthday of 26 March with his father (1963), grandfather (1933) and great-grandfather (1899).Lori Peeler (USA) was born on 13 August 2017 and shares her birthday with her mother (1980), her grandfather (1950) and her great-grandmother (1926).The record-breaking sequence is as follows: Jeannette (13/8/1926), James (13/8/1950), Sarah (13/8/1980) and Lori (13/8/2017).
For a complete list of 2017 records, please visit 2017 Guinness Records in United States.