CASTRATION IN 'SWEET BIRD OF YOUTH'
Castration is a central theme in the play. We hear of a black man being castrated before the play begins...
Scotty: 'They picked out a n*gger at random and castrated the b*stard to show they mean business about white women's protection.'
When Boss Finley is addressing this issue at his political rally, he makes the statement, 'I can't and will not accept, tolerate, condone this threat of a blood pollution.'
It becomes obvious here that, despite his denial, that it is quite obvious that racist Finley gave his cronies the go ahead to castrate the black man to serve as a warning to all others who may try and 'contaminate' the pure white women of the south.
CASTRATION OF HEAVENLY
Heavenly contracts a venereal disease through sexual relations with gigolo, Chance. In order to rid herself of such a disease, she had to undergo a hushed up hysterectomy, much to the embarrassment of Boss.
Boss: My daughter's no whore, but she had a whore's operation.
'Papa, I'm sorry my operation brought this embarrassment on you [...] I felt worse than embarrassed when I found out Dr George Scudder's knife had cut the youth out of my body, made me an old childless woman. Dry, cold, empty, like an old woman.
Princess' comment on Heavenly's hysterectomy:
'[you] put such rot in her body she had to be gutted and hung on a butcher's hook like a chicken dressed for Sunday.'
Tom Junior on Heavenly's hysterectomy:
'she didn't know about the diseases of whore...she had to be cleaned and cured...spayed like a dawg'
Heavenly jokes that 'the embalmers must've done a good job' on her, this suggesting that although she may look like a living, breathing young girl, inside she is essentially dead, her hysterectomy has taken the youth, purity, innocence and enjoyment out of her life.
CASTRATION OF CHANCE
Chance is threatened with castration throughout the play, but his refusal to leave means he ends up getting what he is promised with throughout:
Tom Junior threatens Chance after discussing what he did to his sister (the 'cleaned and cured...spayed like a dawg' speech')
'If you're still here after this rally, you're gonna get the knife too.'
However, Chance accepts his castration, he puts up no fight. Although the play takes place on Easter, Chance is by no means a Christ figure. His refusal to flee is simply a redemptive act fit to be carried out on the anniversary of a far greater passion. At the end of the play, Chance turns to the audience to say,
'I don't ask for your pity...just for your recognition of me in you, and the enemy, time in us all.'
Although Chance is physically castrated, time has also castrated him- it ends his youth, it ends his livelihood, it leaves him with nothing to show for his life as up until now, he has relied solely on his looks. In this sense, Princess cannot turn back the clock either, so she also has been castrated in a sense.
CASTRATION OF BOSS FINLEY:
Boss Finley is never physically castrated, but he is in a sense. We're told by Tom Junior that Miss Lucy, Boss' mistress, has publicly ridiculed him,
'She says you're too old for a lover...'Boss Finley' she wrote, 'is too old to cut the mustard.''
Boss is castrated by this public ridicule that Miss Lucy has thrust upon him. His sense of sexual pride takes a beating and he is publicly emasculated, he is made the laughing stock of St. Cloud, which for such a serious, straight-laced politician is incredibly harrowing and embarrassing.
Hope this helps!
EDIT: Also, a good quote for Heavenly's is made by the Heckler: 'did she put on black in mourning for her appendix?' The Heckler is distinctive in this play as the only voice of conscience. He alone protests the hypocrisy and shame of all those around him. Although he does not wish to hurt Heavenly, he does highlight the hypocrisy of Boss' crusades for purity, when even his own daughter is tainted.