What opportunities are available to people who major in child development?

There are lots of internships and volunteer work that involve working with children - for example, research assistant positions in labs, tutoring/teaching, camp counseling, etc. Career-wise, you can go in a more academic direction by continuing to research children (as a professor, lab manager, graduate student, or researcher), or you can apply your work to any field involving children. For example, you could go to medical school and become a child psychiatrist or a pediatrician. You could become a teacher. You could do social welfare work or other work that advocates for the well-being of children. Almost any field has some applicability to children, and what you learn about child psychology and about doing research is likely to be applicable in some fashion.

Almost anything is your work history is outside of Early Childhood Education. However, play therapist and speech therapist are two that may require a masers in other courses.