Check out Fact Quickie: https://www.youtube.com/channel/UCy8LfEjAzL-5ZHgLUmeExUA →Some of our favorites: https://www.youtube.com/playlist?list=PLR0XuDegDqP10d4vrztQ0fVzNnTiQBEAA →Subscribe for new videos every day! https://www.youtube.com/user/TodayIFoundOut?sub_confirmation=1 Never run out of things to say at the water cooler with TodayIFoundOut! Brand new videos 7 days a week! More from TodayIFoundOut: How Exactly Do You Prove You're Alive if You're Accidentally Declared Dead? https://youtu.be/lCbit1NM4FY In this video: Do women’s menstrual cycles sync up over time if they are in close proximity to each other? Being someone who lives with 4 girls and 1 other boy, this knowledge would be very beneficial. I feel like I should know if the estrogen ocean I’m swimming in will have very stormy seas every 28 days. The belief that this occurs is widely known. In 1999, one study reported that 80% of women believe this phenomenon occurs and 70% of them find it pleasant to have this be the case. Want the text version?: http://www.todayifoundout.com/index.php/2013/03/myth-or-fact-womens-menstraul-cycles-synchronize-if-they-live-together-or-are-in-close-proximity-for-large-amounts-of-time/ Sources: https://smartsite.ucdavis.edu/access/content/group/d7cd5927-cc77-43da-857b-3abebfc3d22f/ReadingsIII/Yang-Schank2006.pdf http://www.scientificamerican.com/article.cfm?id=do-women-who-live-together-menstruate-together http://www.sciencebasedmedicine.org/index.php/menstrual-synchrony-do-girls-who-go-together-flow-together/ http://women.webmd.com/tc/normal-menstrual-cycle-topic-overview http://pediatrics.aappublications.org/content/111/4/844 http://www.psych.ucsb.edu/~roney/other%20pdf%20readings/reserve%20readings/wilson.pdf