1. age delays puberty but after day 5 causes interactions of chemicals in the body are
2. earlier onset of puberty (58). not well understood. Simple additive Understanding the chemical interac- models may approximate biological effects
3. tions and the lifelong hormonal implica- at one moment of exposure but such
4. tions of environmental exposures requires models cannot take into account relative
5. careful attention to onset duration and rates of metabolism susceptibility due to