A lot of accounts about why aliens are interested in humans is because they cannot reproduce. This is based on accounts of persons who were abducted. You will also note that many aliens are shown basically as without human reproductive organs or asexual.
For me, I try to understand things in a micro not macro sense. Based on microbiology… ANY intelligent being with our technology can create life in a dish hence them trying to use us to understand how to reproduce does not make sense or I do not buy that scenario.
It is like the Matrix - a great movie with highly aware ideas and philosophy and yet the root reason they gave for keeping humans did not make sense.
For me when something is true all things have to add up unless of course the accounts we get is not true.
Not to discredit these "Credible eyewitnesses" but I believe a certain distinction can be made. That these abductees had sexual acts performed on them would be considered facts or observations. However, I would argue that the assumptions that the aliens are unable to reproduce would be merely that, assumptions.