In addition to being a literal rocket scientist, Karen is a devoted mother and wife. She is completely dedicated to her wife Hen and their young son, Denny. Hen's infidelity with her ex girlfriend (and Denny's biological mother) Eva seriously hurt their marriage. After discovering the affair when Eva attempted to sue the Wilsons for custody of Denny, Karen and Denny temporarily moved in with Karen's parents. However, Karen and Hen eventually reconciled.
In season three, Karen and Hen attempted to have another child. Karen's inability to produce viable eggs crushed her and strained her marriage.