Yes, sex is occurring between genetically / biologically related people, but GSA is something much deeper that that.
Not only is dieting psychologically stressful, it's also biologically stressful—and it may be aging us.
A propensity to cry is, in part, biologically predetermined.
biological bi·o·log·i·cal (bī'ə-lŏj'ĭ-kəl)
Of, relating to, caused by, or affecting life or living organisms.
Having to do with biology.
Related by blood, as in a child's biological parents.