That's why this Texas sodomy law will be struck down.
A man is allowed to perform cunnilingus, but a woman is not allowed to perform cunnilingus.
Nonsense. The 14th Amendment doesn't create a constitutional right to commit sodomy, nor was it intended to do so.
Criminal sodomy statutes in effect in 1868: Alabama: Ala. Rev. Code 3604 (1867). Arizona (Terr.): Howell Code, ch. 10, 48 (1865). Arkansas: Ark. Stat., ch. 51, Art. IV, 5 (1858). California: 1 Cal. Gen. Laws, 1450, 48 (1865). Colorado (Terr.): Colo. Rev. Stat., ch. 22, 45, 46 (1868). Connecticut: Conn. Gen. Stat., Tit. 122, ch. 7, 124 (1866). Delaware: Del. Rev. Stat., ch. 131, 7 (1893). Florida: Fla. Rev. Stat., div. 5, 2614 (passed 1868) (1892). Georgia: Ga. Code 4286, 4287, 4290 (1867). Kingdom of Hawaii: Haw. Penal Code, ch. 13, 11 (1869). Illinois: Ill. Rev. Stat., div. 5, 49, 50 (1845). Kansas (Terr.): Kan. Stat., ch. 53, 7 (1855). Kentucky: 1 Ky. Rev. Stat., ch. 28, Art. IV, 11 (1860). Louisiana: La. Rev. Stat., Crimes and Offences, 5 (1856). Maine: Me. Rev. Stat., Tit. XII, ch. 160, 4 (1840). Maryland: 1 Md. Code, Art. 30, 201 (1860). Massachusetts: Mass. Gen. Stat., ch. 165, 18 (1860). Michigan: Mich. Rev. Stat., Tit. 30, ch. 158, 16 (1846). Minnesota: Minn. Stat., ch. 96, 13 (1859). Mississippi: Miss. Rev. Code, ch. 64, LII, Art. 238 (1857). Missouri: 1 Mo. Rev. Stat., ch. 50, Art. VIII, 7 (1856). Montana (Terr.): Mont. Acts, Resolutions, Memorials, Criminal Practice Acts, ch. IV, 44 (1866). Nebraska (Terr.): Neb. Rev. Stat., Crim. Code, ch. 4, 47 (1866). [478 U.S. 186, 194] Nevada (Terr.): Nev. Comp. Laws, 1861-1900, Crimes and Punishments, 45. New Hampshire: N. H. Laws, Act. of June 19, 1812, 5 (1815). New Jersey: N. J. Rev. Stat., Tit. 8, ch. 1, 9 (1847). New York: 3 N. Y. Rev. Stat., pt. 4, ch. 1, Tit. 5, 20 (5th ed. 1859). North Carolina: N.C. Rev. Code, ch. 34, 6 (1855). Oregon: Laws of Ore., Crimes - Against Morality, etc., ch. 7, 655 (1874). Pennsylvania: Act of Mar. 31, 1860, 32, Pub. L. 392, in 1 Digest of Statute Law of Pa. 1700-1903, p. 1011 (Purdon 1905). Rhode Island: R. I. Gen. Stat., ch. 232, 12 (1872). South Carolina: Act of 1712, in 2 Stat. at Large of S. C. 1682-1716, p. 493 (1837). Tennessee: Tenn. Code, ch. 8, Art. 1, 4843 (1858). Texas: Tex. Rev. Stat., Tit. 10, ch. 5, Art. 342 (1887) (passed 1860). Vermont: Acts and Laws of the State of Vt. (1779). Virginia: Va. Code, ch. 149, 12 (1868). West Virginia: W. Va. Code, ch. 149, 12 (1868). Wisconsin (Terr.): Wis. Stat. 14, p. 367 (1839).
You may have identified why it will be struck down, but not whether or not it should be struck down.
I have no problem with that kind of duality. Can you marry your dog? Why not? It's your dog! "It's not fair that people get to only marry the opposite sex, but I can't marry Sparky..."