Does the obligation to recite the Shema twice each day apply to women, or only to men?
The Shulhan Aruch (Orah Haim 70) invokes in this context the famous principle of "Misvat Aseh She’hazman Gerama," which means that, as a general rule, the Torah absolves women from Misvot that are bound by time. The obligation to recite Shema applies only at very specific periods each morning and evening, and therefore, the Shulhan Aruch rules, it does not apply to women. Nevertheless, he adds, it is proper to instruct women to formally accept upon themselves "Ol Malchut Shamayim" (the yoke of Divine Kingship) each day, by reciting the first verse of Shema ("Shema Yisrael…") as well as "Baruch Shem Kebod Malchuto…"
Is a parent required to train his children to recite Shema each day at the proper time?
Rabbenu Tam (Rabbi Yaakob Tam, France, 1100-1171) was of the opinion that a parent indeed bears such an obligation. In his view, once a child reaches the age of Hinuch (training in Misvot), which is generally assumed to be six or seven, depending on the child’s development, the parent must ensure that the child recites Shema at the proper time each day and night. Before this age, however, a parent is not obligated to train the child to recite Shema, though it is advisable to teach one’s child the verse of "Shema Yisrael" as soon as he begins speaking.
Rashi (Rabbi Shlomo Yishaki, France, 1040-1105) held a different position. In his view, even once a child reaches the age of Hinuch, it is unrealistic to expect a father to oversee his child to such an extent. After all, in many instances, a father simply is not with the child at the time when Shema must be recited. For example, some fathers must awaken early in the morning to pray before the child even wakes up, and then rush out to work. Due to the practical difficulties entailed, Rashi maintained, the Sages did not require a father to train his son to recite Shema at the proper time.
The Shulhan Aruch follows Rashi’s view, and does not require a father to train his son to recite Shema at the proper time each day and night. Nevertheless, he adds, it is proper for one to act in accordance with Rabbenu Tam’s position. Thus, when a parent has the opportunity to ensure that the child recites Shema at the proper time, he should certainly do so, even though this is not required according to strict Halacha.
Summary: Women are exempt from the obligation of Shema, though they should recite the first verse and the verse of "Baruch Shem Kebod" in order to accept upon themselves the yoke of Divine Kingship. Strictly speaking, a father is not obligated to stand over his child each day and night to make sure he recites Shema at the proper time, but he should nevertheless try to do so when this is possible, once a child reaches the age of six or seven.