Glossary
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Seasonal Breeder
an animal that produces offspring only during particular times of year.
SERM
Selective Estrogen Receptor Modulator, such as tamoxifen, which exhibits tissue-selective effects.
Sexual Differentiation
the process by which a developing individual assumes the characteristics of either a male or a female.
Sexual Dimorphism
having two distinct forms (e.g., differences in shape, size, coloring) of individuals within the same species, based on the gender of the individual.
Steroid
molecule synthesized from cholesterol.

contains cyclopentenoperhydrophenanthrene nucleus.
Stilbene
an aromatic hydrocarbon (C14 H12), produced by plants, often used as a phosphor and in making dyes.

backbone structure of several compounds with estrogenic activity (e.g., DES, resveratrol).
Stimulatory hormone
a chemical released from the pituitary gland that elicits a response in a target organ.
System
orderly, interconnected parts.

must be defined by a modifier (e.g., endocrine system).
Testis
male gonad.

produces sperm and hormones (testosterone) necessary for reproduction.