The General Handbook states that certain leadership roles in the Church, such as RS presidency, WM presidency, and Primary presidency, are given exclusively to "adult women."
Sections 9.3.2.1 "Calling a Relief Society Presidency", 11.3.2 "Adult Young Women Presidency", and 12.3.2 "Primary Presidency", Handbook of Instructions, The Church of Jesus Christ of Latter-day Saints (2022), accessed July 25, 2023
9.3.2.1
Calling a Relief Society Presidency
The bishop calls a woman to serve as the ward Relief Society president. If the unit is large enough, she recommends to him one or two women to serve as her counselors. The bishopric considers her recommendations and extends the callings.
11.3.2
Adult Young Women Presidency
The bishop calls and sets apart an adult woman to serve as the ward Young Women president. If the unit is large enough, she recommends one or two adult women to be called as her counselors (see chapter 30). The bishopric considers her recommendations and extends the callings.
12.3.2
Primary Presidency
The bishop calls and sets apart an adult woman to serve as the ward Primary president. If the unit is large enough, she recommends one or two adult women to be called as her counselors (see chapter 30). The bishopric considers her recommendations and extends the callings.