…er, when there’s a lot of sunlight. As a result, the fetuses’ increased levels of testosterone can “delay the maturation of the left brain hemisphere during embryonic development,” meaning that the more testosterone a fetus has, the weaker their lef…Why Men Are More Likely To Be Left-Handed413Ilana GordonWiktor ChojnackiFollowFeb 25, 2017 · 1 min readWhy shouldn’t it delay the maturation of the right brain hemisphere, too?