Building Blocks of STEM Act This bill instructs the National Science Foundation (NSF), when awarding grants under the Discovery Research PreK-12 program, to consider age distribution in order to more equitably allocate funding for research studies with a focus on early childhood. The bill directs the NSF to award competitive grants to institutions of higher education or nonprofit organizations to accelerate research efforts to increase understanding of the factors that contribute to the willingness or unwillingness of girls under the age of 11 to participate in STEM (science, technology, engineering, and mathematics) activities. The NSF shall also award competitive grants for such institutions and organizations to enter into partnerships with local educational agencies or states to develop and evaluate interventions in pre-K and elementary school classrooms that seek to increase participation by such girls in computer science activities. The bill amends the National Science Foundation Authorization Act of 2002 to authorize the NSF to award grants under the Robert Noyce Teacher Scholarship Program for the recruitment and training of informatics and computer science teachers.