Back in the "bad old days" of the simplex NCP protocol [1], before the full duplex TCP/IP protocol legalized same-sex network connections, connect and listen sockets had gender defined by their parity, and all connections were required to use sockets with different parity gender (one even and the other odd -- I can't remember which was which, or if it even mattered -- they just had to be different).

The act of trying to connect an even socket to another even socket, or an odd socket to another odd socket, was considered a "peculiar error" called "homosocketuality", which was strictly forbidden by internet protocols, and mandatory "heterosocketuality" was called the "Anita Bryant feature" [2].

http://www.saildart.org/IMPSER.DOC[SS,SYS]

When the error code is zero, the next 8 bit byte is the Stanford peculiar error code, followed by 72 bits of the ailing command returned. Here are the Stanford error codes. [...]

IGN 3 Illegal Gender (Anita Bryant feature--sockets must be heterosocketual, ie. odd to even and even to odd) [...]

Illegal gender in RFC, host hhh/iii, link 0

The host is trying to engage us in homosocketuality. Since this is against the laws of God and ARPA, we naturally refuse to consent to it.

http://www.saildart.org/FTP.NCP[S,NET]

    ; Try to initiate connection

    loginj:
            init log,17
            sixbit /IMP/
            0
            jrst noinit
            setzm conecb
            setom conecb+lsloc
            move ac3,hostno
            movem ac3,conecb+hloc
            setom conecb+wfloc
            movei ac3,40
            movem ac3,conecb+bsloc
            move ac3,consck
            trnn ac3,1
                jrst gayskt            ; only heterosocketuals can win!
             movem ac3,conecb+fsloc
             mtape log,[
                   =15
                    byte (6) 2,24,0,7,7
                         ]          ; Time out CLS, RFNM, RFC, and INPut

    [...]

    gayskt:    outstr [asciz/Homosocketuality is prohibited (the Anita Bryant feature)

    /]

        ife rsexec,<jrst rstart;>exit       1,

(The PDP-10 code above adds the connect and listen socket numbers together, which results in bit 0 being 0 if they are the same gender, then TRNN is "test bits right, no change, skip if non zero", which skips the next instruction (jrst gayskt) if they different sex.)

[1] https://en.wikipedia.org/wiki/Network_Control_Program

[2] https://www.youtube.com/watch?v=H-A2Ql81WTY