What's the opposite of biological control?
For instance, an infant can't control it's bladder. What word should I use?
Those functions are learned, and controlled by the brain. Take breathing, it is controlled by the sympathetic nervous system, but then, we can hold our breath, so the concious can exercise some control. So it is with the bladder and urinary control, the conscious (learned control) can take over. So the word I think you are looking for is cognitive neurological control. Some simpler folks call this self-control.
http://en.wikipedia.org/wiki/Sympathetic_nervous_system
It depends on what function you are talking about. With your infant, bedwetting is enuresis. With lack of conscious bowel control, it is called encopresis.
However, this is lack of conscious control over these functions. These functions are still biologically controlled, but not at the conscious level.
I don't know if this helps you.
The opposite of biological control, in the context you mentioned, would be "lack of control" or "involuntary." In the specific example you provided, where an infant is unable to control its bladder, you can say that the infant lacks bladder control or is experiencing involuntary bladder movements.
To determine the opposite of a term, it is often helpful to consider the meaning of the term and identify a concept that represents the opposite idea. In this case, biological control typically refers to an organism's ability to regulate or manipulate a biological process consciously, while lack of control refers to the absence or inability to regulate that process.