Feodor Vassilyev (Russian: Ѳеодоръ Васильевъ) (c. 1707-1782) was a peasant from Shuya, Russia. His first wife, Mrs. Valentina Vassilyeva sets the record for most children birthed by a single woman. She gave birth to a total of 69 children; however, few other details are known of her life, such as her name, date of birth or death. She gave birth to 16 pairs of twins, 7 sets of triplets and 4 sets of quadruplets between 1725 and 1765, in a total of 69 births. 67 of her children were reported to survive infancy. Vassilyev also had 18 children with his second wife, who had 6 pairs of twins and 2 sets of triplets, making him a father of 87 children in total. Of his 87 children, at least 82 are said to have survived infancy.
The first published account about Feodor Vassilyev's children appeared in a 1783 issue of The Gentleman's Magazine (Vol. 53 p. 753, London, 1783) and states that the information "however astonishing, may be depended upon, as it came directly from an English merchant in St Petersburg to his relatives in England, who added that the peasant was to be introduced to the Empress". The same numbers were given in an 1834 book of Bashutskiy, Saint Petersburg Panorama.
Several published sources raised doubts as to the veracity of these claims. According to a 1933 article by Julia Bell in Biometrika, a 1790 book of B. F. J. Hermann Statistische Schilderung von Rußland did provide the claims about Feodor Vassilyev's children but "with a caution". Bell also notes that the case was reported by The Lancet in an 1878 article about the study of twins. The Lancet article states that the French Academy of Sciences attempted to verify the claims about Vassilyev's children and contacted "M. Khanikoff of the Imperial Academy of St Petersburg for advice as to the means they should pursue, but were told by him that all investigation was superfluous, that members of the family still lived in Moscow and that they had been the object of favours from the Government". Bell concludes that Vassilyev's case "must be regarded as under suspicion". Similarly, Marie Clay in a 1998 book notes: "Sadly, this evasion of proper investigation seems, in retrospect, to have dealt a terminal blow to our chances of ever establishing the true detail of this extraordinary case".
- Letters "The gentleman's magazine, and historical chronicle". The Gentleman's Magazine 53: 753. 1783.
- Clay, Marie M. (1989). "Feodor Vassilyev: a case of remarkable fecundity". Quadruplets and Higher Multiple Births. London: Mac Keith Press. pp. 96–97. ISBN 0-521-41223-4.
- Young, Mark C. (1998). The Guinness Book of World Records. Bantam Books. p. 357. ISBN 0-553-57895-2.
- Bashutskiy, A. P. (1834). Saint Petersburg Panorama vol. 2 (in Russian). St Petersburg. p. 75.
- Bell, Julia (1933). "Plural birth with a new pedigree". Biometrika 25 (1–2): 110–120. doi:10.1093/biomet/25.1-2.110. JSTOR 2332266.
- "Twins". The Lancet 111 (2843): 289–290. 1878. doi:10.1016/S0140-6736(02)42845-0.