Ask A Scientist Molecular Biology Archive

name         Debbie G.
status       other
age          20s

Question -   What is it called when an animal can change sex according
to environmental conditions?  Is it hermaphrodite?  Is there a name for
the actual process?
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Dear Debbie,

A difference between the genetically programmed (i.e. genotypic) sex and the actual 
(i.e. phenotypic) sex of an individual is referred to as "sex reversal" if they're 
phenotypically either male OR female.  Although the phenotype of a hermaphroditic 
animal also differs from its genotype, they have the ability to produce both eggs 
AND sperm.

The actual mechanism of this response to environmental stimuli is not completely 
understood, but most likely involves hormonal signalling.  The following webpage 
from the Univ. College-London has a detailed explanation of this phenomenon 
in humans:

http://www.ich.ucl.ac.uk/cmgs/sexrev.htm

Thanks for the great question & I apologize for the long delay in responding,

Jeff Buzby, Ph.D.
CHOC Research Institute

NEWTON AAS
Div. of Educational Programs
Argonne National Laboratory
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