Are there any causes besides genetics of developing scid?

Yes: If you have received the diagnosis of genetic severe combined immunodeficiency, implying mutations in specific genes, then it is strictly genetic. If you have less defined deficiencies of t-cells (viral. Fungal defense) or b-cells/immunoglobulins (bacterial defense), these can be acquired (e.g., aids) or transient (e.g., hypoglobulinemias) due to chemicals, infections, or cancer.

SCID: None that have been discovered unless the newborn had a serious or severe cancer/leukemia requiring chemotherapy and radiation which wipes out the immune system. Additionally, certain diseases (itp, etc.) that require strong therapy (rituxan) can wipe out the immune system.