His birthdate is uncertain. The first record I’ve found for him, the 1860 census, gives his age as 17, which assuming a birthdate in November would imply 1842. (I’ve not found the 1850 census reading for his parents, despite an exhaustive search including first names only.) He is recorded as 30 in 1870 and 40 in 1880, suggesting a birthdate in 1839. (Since November is after all the census dates, you have to subtract the age plus one from the year.) The 1900 census says Nov 1843. His death certificate, however, says 1845.

The spacing between children is loose enough that anything from 1841 through 1844 would work, although the earlier date pushes William back a bit and the later one pushes Prudence towards the late end of her range. 1842 and 1843 seem most likely.

His death certicate records Mart Sexton, age 67 years 8 months 26 days, born 14 Nov 1845 in Menifee Co., Ky, died 10 Aug 1913 in Forge Hill precinct, Bath Co., Ky, marital status blank, brick mason, father William Sexton, mother’s maiden name Mary McVey, both born in Kentucky, cause of death cancerous prostate, informant Harve Sexton, Owingsville, Ky, burial in Old Virginia Cemetery.

Her death certificate records Mary A. Sexton, age 79 years 2 months 20 days, born 12 Sep 1836 in Bath Co., Ky, died 2 Dec 1915 in Forge Hill precinct, Bath Co., Ky, widowed, father Stribbie Tincher, mother’s maiden name Nancy Crump, both born in Bath Co., Ky, cause of death lobar pneumonia, informant Harve Sexton, Owingsville, Ky, burial in Old Virginia graveyard.

1870 census of Bath Co., Ky, Wyoming precinct, lists as household #76:
Anthony Latham, 20, laborer; Nancy A., 18; Martin Sexton, 30, laborer; Mary, 30; Della, 10; Lewis, 1. All born in Ky.

Della should be listed as a Craig. She is Mary’s daughter from her first marriage.

1880 census of Bath Co., Ky, Owingsville precinct, enumerated 30 June, lists on p. 51 as family #453/455:
Sexton, Marcus, 40, brickmason; Mary, 40, wife; Louis, 9, son; Frank, 7, son; William, 5, son; Harvey, 3, son; James, 1, son. Craig, Delie, 17, boarder.

1900 census of Bath Co., Ky, Wyoming precinct, enumerated 9 June, lists on p. 5A as family #90:
Sexton, Martin P., 54, b. Nov 1843, brick layer and plasterer; Mary A., wife, 63, b. Sep 1836, married 32 years, mother of 10 children, 8 living; James R., son, 21, b. July 1878; Charley E., son, 19, b. Apr 1881. All born Ky Ky Ky.

Note that Martin and Mary, who were recorded as being the same age in 1870 and 1880, are here listed as 9 years apart! Also note that the age given for Martin does not match the reported birthdate.

The next household is headed by Abby Sexton (nee Craig), widow of Martin’s brother Presley.

1910 census of Bath Co., Ky, Wyoming precinct, enumerated 27 April, lists on p. 5B as family #60:
Sexton, Martin P., 64, first marriage, married 41 years, brick layer; Mary A., wife, 73, married 41 years, mother of 10 children, 7 living.

The next household is headed by their son Louis.