If the teacher said, “when you have your own kids, you’ll understand”, would she be brainwashing the students into marriage and having kids?
No, “the teacher” would be brainwashing NOT to have children 😉
That being said, it depends on the context and whether it is systematic. If the course is regarding diaper changing and it is in the open, then no. Once again from Wikipedia:
Mind control (also known as brainwashing, coercive persuasion, mind abuse, menticide, thought control, or thought reform) refers to a process in which a group or individual “systematically uses unethically manipulative methods to persuade others to conform to the wishes of the manipulator(s), often to the detriment of the person being manipulated”.[1] The term has been applied to any tactic, psychological or otherwise, which can be seen as subverting an individual’s sense of control over their own thinking, behavior, emotions or decision making.
(Emphasis added).
Each case has to be looked at in context to see whether the Da’as of a person is being subverted.