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Name: Debbie G.
Status: Student
Age: 20s
Location: N/A
Country: N/A
Date: August 2004

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?

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:

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

Jeff Buzby, Ph.D.
CHOC Research Institute
Div. of Educational Programs
Argonne National Laboratory

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