About Us


ThoughtSTEM was founded by 3 UCSD PhD Students in October of 2012. What started as tutoring business with 5 students has swiftly grown into a county-wide service that has brought students starting at age 6 together throughout San Diego to explore, learn, and have fun!

Stephen Foster, PhD - CEO

A PhD graduate from UCSD in the field of Computer Science, Stephen is particularly interested in researching gamification as it applies to Computer Science Education. Learn more about Stephen on his:

Dr. Lindsey Handley, PhD - COO

Lindsey earned her PhD at UCSD conducting research in the Department of Chemistry and Biochemistry. Lindsey has a passion for teaching science & technology to kids. Learn more about Lindsey on her:

Dr. Sarah Guthals, PhD - Emeritus

As a PhD graduate from UCSD, Sarah researches Computer Science Education, finding new ways to support learners when there isn't a teacher physically near them.


ThoughtSTEM wouldn't be able to succeed without the advice from those who support us. This group of people have varying expertise and experience that have helped us better understand our students, our curriculum, and our business.

Dr. Beth Simon, PhD

Dr. Simon is an expert in Computer Science Education. She has developed many computer science courses for high school and undergraduate students. Dr. Simon is also an expert in distance learning and pedagogies. She is an active member in the computer science education research community. Specializes in:

  • Introductory Computer Science Courses
  • AP Computer Science Course Curriculum
  • Innovative Pedagogies
  • Distance Learning

Jennifer Arguello

Jennifer is an expert in computer science educational technologies. She also has over a decade experience with technological and educational startups. Jennifer is also our Industrial Mentor for the I-Corps NSF grant that we received for our CodeSpells Software! Specializes in:

  • Lean Startup Methodology
  • Educational Technologies

Dr. Ed Abeyta, PhD

Dr. Abeyta is currently the Director of K-16 Programs for UCSD Extension. He is a critical partner of ThoughtSTEM as we are working towards building a College Prep STEAM academy with UCSD Extension. Specializes in:

  • Course Accreditation
  • K-16 Students
  • Course and Camp Logistics

Administration and Faculty

ThoughtSTEM has a talented group of employees to set up and manage our programs.

Judith Eisenberg - Lead Teacher

Judith received her Bachelor's degree in Mathematical and Computational Sciences from Stanford University. Prior to joining ThoughtSTEM, she worked in Silicon Valley for several high-tech companies and in San Diego in the non-profit world. At ThoughtSTEM, she is responsible for maintaining the website, assisting with payroll and HR, as well as as being an instructor.

Cristina Gerardi - Lead Teacher

Cristina studied music at San Diego State University and Grossmont College, as well as completing multiple workshops in early childhood development. She has worked with children as an instructor and in many other capacities. She enjoys making complex concepts simple, incorporating visual and tactile tools in the classroom.

Carlos Herrera - Lead Teacher, Program Resource Developer/Trainer and Curriculum Developer

Carlos is a Community College student at mesa college working on transferring as a Cognitive Science major. He has done research and development in STEM education to find the best way to teach Computer Science concepts to kids. When he isn't in the classroom teaching, Carlos is creating mods or working with teachers from all over the country to optimize their experience with LearnToMod. He specializes in:

  • Curriculum Management
  • Instructional Design
  • Web Development
  • Resource Training

Jason Le - Lead Teacher & Curriculum Developer of After-school Programs

As a graduate of Cal State Long Beach with a bachelor’s degree in Computer Engineering and a minor in Computer Science, Jason has worked on projects ranging from software applications to scratch built autonomous vehicles. His love for technology is equally matched by his passion for mentoring. He has designed, developed, and taught K-12 technology curriculum for various summer tech camps as well as in-school electives and after school programs. He specializes in:

  • Embedded Software Development
  • Electrical Engineering
  • Arduino
  • Robotics
  • App Development
  • Game Design

Sara Lucchini - Lead Teacher

Sara is a Lead Teacher at ThoughtSTEM. She delights in sharing joy through teaching and creating an environment where learning is an exciting journey led by the student's desire for knowledge. Sara has a degree in Theatre Performance and Education from Juniata College.

David Macatantan - Lead Teacher

David Macatantan received his Bachelor's from Ex'pression College for Game Art & Design. He is an experienced 3D modeler and 3D animator that enjoys sharing his computer knowledge to growing minds. With his passion for games, he helps students enjoy learning about computer programming.

Sonny Najar - Lead Teacher for After-School Program and Content and Curriculum Developer

Sonny has a B.S. in Computer Science from SDSU. He currently is a Lead Educator in several of ThoughtSTEM's After School Programs, where he implements the techniques he learned in college to explain programming concepts. Sonny applies his knowledge of CS on several other areas of the company:

  • Curriculum Development
  • Software Content
  • Website Development

Jeron Paraiso - Software Developer

Jeron is a full-stack web-developer, who loves to hack on games and websites. Also, he loves to teach and think of interesting ways to conceptualize computer science or the flow of computers running programs. Currently, he is working on an interactive text based game in the JavaScript programming language.

  • After-school programs
  • Weekend workshops