In the case of the evolutionary biologist, successful procreation does not require any knowledge of biology.
When it comes to planes, there is a high correlation between the quality of the plane and the quality of the design.
Maybe this is a good point. I would argue that a high school kid who knocks up his girlfriend has demonstrated a better intuitive grasp of biology than my PhD friend.
Not even a little. The high school students are slaves to unconscious drives in their bodies and that's not even related to having an understanding of biology. Or do you say that a world expert in biology who would rather spend their time furthering studies than raising a child actually knows less about biology than rabbits? Your arguments aren't making any sense.
A bacterium can perform cell division, but it can't explain it. The evolutionary biologist's job isn't to personally have sex, it's to explain what happens when many generations of organisms do so.