Walter Clyde Curry, in an influential work on Chaucer and the Medieval Sciences, New Haven, 1926 [Widener 12422.165, Lamont PR1933.S3 C8], pp. 59-70, argues that the Pardoner is a eunuch, a "eunuchus ex nativitate"; his lack of facial hair and high voice are attributes commonly associated with this condition. Beryl Rowland, using modern medical texts, defines him as "testicular pseudo-hermaphrodite of the feminine type" [Neophilologus, 48, 1964, 56-60]. Others, accepting the assumption the Pardoner is a eunuch, see him as a spiritual symbol, the opposite of the "eunuch of God":
Robert P. Miller, Chaucer's Pardoner, The Scriptural Eunuch, and the Pardoner's Tale, Speculum 30 (1955), 180-89 (This article is in JSTOR which is available only to subscribing institutions.)
More recently, critics have argued for the position that the Pardoner is a homosexual; see especially:
Monica McAlpine, The Pardoner's Homosexuality and How It Matters, PMLA 95, (1980), pp. 8-22.
C. David Benson and R.F. Green argue that the Pardoner is an effeminate heterosexual and womanizer (somewhat like Absolom in the Miller's Tale).
David Benson, "Chaucer's Pardoner: His Sexuality and Modern Critics," Medievalia 8 (1985 [for 1982]), pp. 337-46.
Richard F. Green, "The Sexual Normality of Chaucer's Pardoner," Medievalia 8 (1985 [for 1982]), 351-57.
This (both C.D. Benson and R.F. Green argue) is the view of the author of The Prologue to the Tale of Beryn, a fifteenth-century continuation of The Canterbury Tales in which the Pardoner is the eager but unsuccessful wooer of the barmaid Kit at the tavern where the pilgrims are lodged:
Prologue to The Tale of Beryn
The author of the Tale of Beryn gives us the only interpretation of the Pardoner by an early reader of Chaucer. The character appears but briefly in Lydgate's continuation of The Canterbury Tales, his prologue to The Sege of Thebes, where he is confused (or rather merged with) the Summoner, his companion in the General Prologue:
Prologue to The Sege of Thebes
What Lydgate meant by this confusion or merging of the two characters (if anything) is not at all clear. There are no other clues to the Pardoner's sexual identity in early comments on Chaucer's tales. And Chaucer -- who says only "I trowe" he is a gelding or mare -- leaves the solution of this problem up to his readers. That may be the most important clue of all.