Joseph Emory DAVIS had no known children with his wife, Eliza VAN BENTHUYSEN, but he acknowledged three illegitimate children (viz., Florida Ann, Mary Lucinda, and Caroline) and adopted two other children (viz., the infant son of Jane NICHOLSON and Martha QUARLES).  I know of no documentation supporting that Joseph Emory DAVIS had an illegitimate son, and the fact that he openly acknowledged three illegitimate daughters and adopted two other children makes it highly improbable that, if he had a biological son, he wouldn't have at least acknowledged him, if not adopted him.

Joseph's father, Samuel Emory DAVIS, was born in Georgia and moved to Kentucky by 1797 — Samuel is on the 1800-1808 tax rolls of Christian Co., KY, with land on the West Fork of Red River.  As a boy of 13-yrs in 1797, Joseph would have made the move from Georgia to Kentucky with his parents.  Samuel then moved his family to Mississppi in 1808.  That Joseph moved with his parents is supported by the fact that Joseph's eldest daughter, Florida Ann, was born in 1811 in Mississippi.

Daniel SHELBY is on the on the tax rolls of Christian Co., KY, from 1807 to 1809, with land on the West Fork of Red River; he is the only SHELBY in the county during those years.  One can argue that Joseph Emory DAVIS had a dalliance with a daughter of Daniel SHELBY, but where's the evidence?  One can argue that Rachel SHELBY was that daughter of Daniel SHELBY, but where's the evidence?  One can argue that a son, William, was the product of that dalliance, but where's the evidence?  And only if William was born in Kentucky is such a contention even plausible.  If William was born in either IL or SC, it becomes highly improbable that he is Joseph's son. 

Martha married William DAVIS as Mrs. Martha L. CRAWFORD, so are we certain her maiden name was also CRAWFORD?

1.  Illinois Statewide Marriage Index, 1763–1900:

Davis, William (of White Co)	Crawford, Maria	Gallatin	07/16/1827
Davis, William	Crawford, Martha L (Mrs)	Gallatin	12/08/1887
Glass, Franklin S	Davis, Martha L	Gallatin	11/21/1896

2.  1830 Census Index/Images (online at Ancestry.com):  no William DAVIS in Gallatin Co., IL.  Of the two William DAVIS'es in White Co., IL, one is too old to be our subject and the other, while he is in the right age class and has one daughter, he has no sons (00001-10001).

4.  1840 Census Index/Images (online at Ancestry.com, Image #3-4 of 6; extracted by Diana Gale Matthiesen):

1840

IL

Gallatin Co.

North Fork Precinct

pp. 60B-61A

Ln. 9

William Davis

001 011 - 101 001

0100000

These data indicate:

No. & Sex	Age Class	Therefore Born	Individuals Inferred
1 male	10-14	1825-1830	= James (b. 1827/8)
1 male	20-29	1810-1820	= ?
1 male	30-39	1800-1810	= William (b. 1808)
1 female	4 or under	1835-1840	= Lucinda (b. 1836/7)
1 female	10-14	1825-1830	= Nancy (b. 1830)
1 female	30-39	1800-1810	= Mary (b. 1808)
1	person employed in agriculture

The male in his 20s is too old to be their son.

5.  1850 Census Index/Microfilm (online at GenealogyLibrary.com):  North Fork Precinct, Gallatin Co., IL, p. 370B, 33/33, enumerated 3 Sep 1850 (extracted by Diana Gale Matthiesen):

William Davis	41	M	Farmer	300	S.C.
Mary      "	42	F			Ill.
James H.  "	22	M	Laborer		"
Lucinda   "	13	F			"
John E.   "	10	M			"

6.  1860 Census Index/Images (online at Genealogy.com, Image #4-5 of 7):  Crawford P.O., T8_.R8E, 3rd PM, Gallatin Co., IL, Roll 180 (Book 1), pp. 1049-1050, 1340/1340, enumerated 18 Aug 1860, official enumeration date 1 Jun 1860 (extracted by Diana Gale Matthiesen):

William Davis	53	M		Farmer	1000	500	Illinois
Mary	53	F					Illinois
John	18	M					Illinois
Elizabeth	30	F					Illinois
William J	13	M					Illinois
Lucinda J	8	F					Illinois
[next page]
Rachel J	7	F					Illinois
Garland M	4	M					Illinois

Listed two households from Robert & Martha TROUSDALE, who are three households from John & Nancy CRAWFORD.

7.  1870 Census Index/Images (online at Genealogy.com, Image #39 of 94):  Equality P.O., T8_.R8_, Gallatin Co., IL, Roll 224 (Book 1), p. 351A, PN 23, 173/173, enumerated 9 Jun 1870, official enumeration date 1 Jun 1870 (extracted by Diana Gale Matthiesen):

Davis Wm	61	M	W	Farmer	1000	500	Ky
"   Mary	62	F	W	House Keeper			Ky
Brinkly Mary S	15	F	W				Ills
Brinkly Robt E	13	M	W				Ills

Listed next to son, John E. DAVIS.

8.  1880

9.  Kirk Bentley Barb.  1971.  "Extract from Genealogy of Jefferson Davis."  Appendix III, pp. 488-508 in Papers of Jefferson Davis, Volume 1, 1808-1840.  Haskell M. Monroe, Jr., and James T. McIntosh, eds.  Louisiana State Univ. Press, Baton Rouge.  [Rev. ed. of 1991 not seen.]  No mention of a liaison between Joseph Emory DAVIS and Rachel SHELBY, nor of a son, William DAVIS.

10.  Haskell M. Monroe., Jr. & James T. McIntosh, eds.  1971.  "Genealogy of the Davis Family."  Appendix IV, pp. 505-529 in Papers of Jefferson Davis, Volume 1, 1808-1840.  Louisiana State Univ. Press, Baton Rouge.  [Rev. ed. of 1991 not seen.]  No mention of a liaison between Joseph Emory DAVIS and Rachel SHELBY, nor of a son, William DAVIS.

11.  Ernesto Caldeira.  1983.  "Davis Family Genealogy."  Appendix II, pp. 402-416 in Papers of Jefferson Davis, Volume 4, 1849-1852.  Linda Lasswell Christ, Mary Seaton Dix, and Richard E. Beringer, eds.  Louisiana State Univ. Press, Baton Rouge.  No mention of a liaison between Joseph Emory DAVIS and Rachel SHELBY, nor of a son, William DAVIS.

12.  Genealogy of the Davis Family at Rice University.  No mention of a liaison between Joseph Emory DAVIS and Rachel SHELBY, nor of a son, William DAVIS.

13.  Janet Sharp Hermann.  1990.  Joseph E. Davis, Pioneer Patriarch.  Univ. Press of Mississippi, Jackson, MS (out of print).

Hermann supports a liaison between Joseph Emory DAVIS and Rachel SHELBY in Christian Co., KY, with a resulting son, William DAVIS, b. 1808.  Her sources are entirely secondary.  As she states, "…family tradition has convinced me that William was indeed Joseph's son" Tradition?  As if there weren't hundreds, possibly thousands, of fanciful family legends — all untrue — of being connected to Jefferson DAVIS!

14.  WorldConnect (online at RootsWeb.com).