What are two major themes of the book In Cold Blood by Truman Capote?

In Truman Capote's jounalistic novel, In Cold
Blood, he reports on the horrific crime of the murder of the Clutter family
while examining closely the men who committed this crime.  Capote particularly found
Perry Smith fascinating.  His visits and conversations with Perry led Capote to raise
the question of whether a man alone can be held responsible for his actions when his
environment has deprived him of what is essential to a human being.  This exploration
into the psyche of Perry Smith develops the theme of Nature vs.
Nurture.  Were Perry's crimes the acts of one who was inherently evil, or
did they stem from his neglect?

Another theme in Capote's
book is that of Sexuality.  Hickock who cannot be satisfied
with monogamy has been married twice.  But, he is also perverted as Smith has to prevent
him from raping Nancy Clutter on the fateful night.  Smith, who complains that he cannot
stand people who do not control their sexual urges, seems to struggle against his
homosexuality.  He constantly tries to prove his masculinity to Hickock, who, in turn,
strives to prove his potential to violence to Smith.