Strength of endogenous pacemakers?

-Supporting research evidnece -Menstrual cycle regulated by the hypothalamus, McClintock also shows the the role of zeigbers that can play a role in ovulation and menstruation. The idea of menstrual synchorny as women can snyc with others due to other women's peromones at different stages of the cycle -However, significant eviednece to falsify the theory including a study conducted by Ziomkieicz foudn in 18 pairs and 21 triplits that menstrual synchony was not found. Social interactions was found to be unrelated to cause any differnece in mentstrual cycle onsets -Supports the role of the endogenous pacemaker and casts doubt onto the influence of exogenous zeitgebers