Fastest marathon run by parent and child (mixed)

According to Official Guinness Records,

The fastest marathon run by parent and child (mixed) is 5 hr 41 min 12 sec by Masako Kataoka and her son Tetsuro Kataoka (both Japan) at the 63rd Beppu Oita Mainichi Marathon in Beppu, Oita, Japan, on 2 February 2014.
The Beppu Oita Mainichi Marathon is sanctioned by the Japan Association of Athletics Federations (JAAF). Tetsuro Kataoka completed the marathon in 2 hr 31 min 20 sec and Masako Kataoka completed it in 3 hr 9 min 52 sec.

For a complete list of 2014 records, please visit 2014 Guinness Records in Japan.

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