Some Jews feel that singularizing men for tallis and tefillin wearing shows Judaism’s discrimination against females. Rabbi Moshe Feinstein addresses the issue (Igros Moshe, Orach Chaim 4:49), explaining that this exclusion does not in any way indicate a lower or lesser holiness or piety level attainable by women. While there are surely hidden reasons for obligating or excusing certain people from certain mitzvos, the obvious reasons are that women are naturally entrusted with more childcare obligations than men are, a mission essential for Jewish survival and perpetuation of Torah in the future generations. This mission requires peace of mind and removal of all external distractions. Therefore, women are excused from various mitzvos that occupy one’s time or full concentration such as Torah study.
Rabbi Feinstein adds that in the natural world most females are entrusted with the majority of childcare duties, and mankind is no different. Ladies (or men) who insist on forcing nature to accommodate their idea of equality (such as sending women out to combat service) do not believe in the Torah and have no portion in the World to Come.
