Gender metamorphosis at work
It’s a girl! …right? Sometimes, the answer is not so clear. In an
isolated village in the southwestern region of the Dominican Republic
and in the eastern highlands of Papua New Guinea, amazing cases of
natural gender transformation in human populations have been reported.
Some males with female phenotypes at birth begin to develop physical
male characteristics during puberty. This phenomenon poses many
challenging questions about what defines gender and how societies shape
their concepts of it.
In the 1970s, Julianne Imperato, PhD, of
Cornell University traveled to the Dominican Republic to investigate
claims of young female-appearing children developing masculine
features. The locals referred to the phenomena by two names:
guevedoces, translated to mean “penis at age twelve,” and machihembras,
meaning “first a woman, then a man.” In the following years, reports
suggested that this was also common in the Sambian villages of Papua
New Guinea, where the locals called these individuals turnims, meaning
“expected to become men.”
The guevedoces, machihembras, and turnims
are born with an XY genotype and both sex chromosomes intact. During
fetal development, the sex determining region of the Y chromosome (SRY)
inhibits female internal sexual organ development and induces the
development of internal male sexual organs. Both guevedoces and normal
male fetuses possess functioning SRY.
But what causes these males to appear
female? They seem to lack functioning copies of the 5 α-reductase
enzyme, which converts testosterone to the biologically active
dihydrotestosterone (DHT). In the absence of DHT, the postnatal
external genitalia appear to be an ambiguous clitoris and labia.
In the past, guevedoces were automatically
regarded as females and raised as such. As any normal male would,
guevedoces have a sudden increase in testosterone levels during
puberty, which may cause the clitoris to enlarge. This surge of
testosterone, in turn, may be responsible for the initiation of normal
male sexual development and often results in the growth of facial and
body hair and the deepening of the voice. Subsequently, most guevedoces
spend their adult years resembling sexually normal males, though subtle
differences still exist. For example, most have decreased amounts of
facial hair and smaller prostate glands relative to the average male.
Research has shown this genetic disorder
to be of autosomal recessive inheritance. Due to the decreased size of
the gene pool in these communities as well as their isolation from
other populations, this condition persists for generations.
During the 1970s, guevedoces births were reported to account for as many as two percent of all births in these small villages of the Dominican Republic. Since then, doctors in villages in both the Dominican Republic and Papua New Guinea have become experts in distinguishing normal female external genitalia from the ambiguous genitalia of guevedoces babies. Due to the prevalence of these births, both cultures believe in three sexual categories: the male, the female, and the pseudohermaphrodite.
The differences in the way these two
societies deal with this rare occurrence hint at the magnitude to which
a society’s culture can affect an individual’s beliefs and opinions.
The Sambians view these children as flawed males; the children are
rejected and humiliated by their families and society. On the other
hand, in the Dominican Republic, the birth of a psueodhermaphrodite is
fully accepted and during puberty, the child’s physical transformation
into a male is marked by joyous celebration. Gemma Nierman, PhD, of St.
Mary’s College and summer lecturer at University of California,
Berkeley, remarks, “the Dominican Republic communities that quietly
accept their citizens with 5 α-reductase deficiency are a model to the
world on how to deal with genetic differences...[they] are showing us
how to help these folks have a full and rewarding life despite their