The first conversation I had with Boyan, was about whether or not cows had to have been pregnant to produce milk. I contended that they had to have been pregnant at least once before producing milk, and given hormones there after to continue producing milk.
Boyan disagreed with me. (He still disagrees with me...)
Then, tried to tell me that you could milk a dolphin. We still have this argument to this day.
"I'm a mammal Greg. Can you milk me?"