One of my ancestors married one of Robert McWhorter's many nieces. A well-meaning Tennessee relative sent me the following information, which I haven't verified because my connection was so distant and tenuous. Still, I kept the information (just in case).

My information indicates that your Robert H. McWhorter was born in 1807, Casey Co., KY. He married Juliana Royalty Hight on December 30, 1829 in Casey Co. Eight known children of Robert and Juliana are: Elijah Franklin b. 11 January 1831; Emily b. 1832; Caroline A. b. 1835, Elizabeth W. (Betsy) b. 1837; Sarah P. (Sally) b. 1839; Jesse W. b. 1842; Artemesia b. about 1845; and John H. b. 22 March 1845. Not sure if Artemesia and John were twins or not.

Robert H. McWhorter's parents were John McWhorter, Jr. and Elizabeth McClure. It was the second marriage for John McWorter, Jr., and her only marriage. John McW. Jr. was born 1748-1749 Albemarle Co., VA. and died June 1833 in Casey Co.,KY. He married Elizabeth McClure about April 1784, probably at Union Co., S.C. She was born about 1763 and died about 1841. This couple had eight known children, of whom your Robert H. was the youngest. John McWhorter, Jr. was first married (about 1773) to Elizabeth Mary Jasper, who was born about 1752 in Albemarle Co., VA. John McW. Jr. and Elizabeth Jasper had three children. John McWorter, Jr. also marrried a third time, time and place unknown to me, to Elizabeth Haney. Apparently there were no children from this third marriage. Elizabeth Haney was born about 1770.

Your Robert H. McWhorter had 3 half siblings (see previous paragraph). His three half-siblings (by his father's marriage to his step-mother Elizabeth Jasper) were:
1. George b. 1775 Albemarle Co., VA d. 1840 TN
m. Agnes Ann Simpson in 1799 -- they had 5 known children
2. Jesse b. abt. 1778. He didn't marry. He lived with his half-brother (your Robert). While on military duty, he was captured and tortured by Indians, which left him permanently crippled.
3. James W. b. abt. 1782, d. about 1815 Clay Co., KY.
m. Nancy Pigg in 1804 -- they had 3 known children.

Your Robert H. McWhorter had 8 full siblings:
1. Sarah b. 17 January 1786 d. 5 October 1857
m. Lewis Pigg in 1805 -- they had 9 known children.
2. Elijah b. 1790 d. abt. 1866
m. Mary Pigg in 1811 -- they had 10 known children.
3. William T. b. 8 July 1791 d. abt. 1877
m. Mary Moore in 1819 -- they had 10 known children.
4. Mary b. abt. 1792
5. Willis b. abt 1800 (twin to Wilson?)
6. Wilson b. abt. 1800 (twin to Willis?)
7. John McWhorter III b. 5 January 1802/1803 d. August 1866
m. Elizabeth Hight in 1825 -- 11 known children.
8. Richard W. b. 3 November 1803 or 1804 d. 10 September 1876.
m. Elizabeth Sutherland in 1828 -- 10 known children.

Good luck with your research.