I am writing a proposal with a wonderful young scientist. She has lots of skills I don't. I have lots of skills she doesn't. In a system with two parts, she does all of the beginning up through the interface. I pickup at the interface and carry through the second part. The problem we are addressing has a lot to do with sex differences, and things that NIH should be very interested in funding. We've been working up a feasible joint project for nearly 18 months now. We've met at meetings, and skyped for hours. We wrote an R21. I was PI because she was still a (albeit very senior) postdoc. We got scored, but not funded (I was so relieved not to be triaged).
She got a job that starts this fall, but wanted to resubmit after reading the critiques. Which were, btw, good critiques, things with which we could work, things that we could clarify, and not off-the-wall irritating comments. I offered to wait on the resubmission and let her be PI from her new institution. She said that we were ready to resubmit, and we should just go ahead and do it. I was happy to do whatever she wanted.
One of the critiques is "there is no evidence of collaboration between the two investigators". Well, we haven't published together as these are very expensive experiments for all sorts of reasons. We thought about combining data and doing something just to prove we "can work together" but neither of us felt good about that. It seemed like something that you do to please someone else, not anything that would advance science. In the end, I'm not sure that a male PI would get this critique, or that a big dog would. The assumption is that they would make it work. Maybe I'm just sensitive. Its a great project. It has the potential to make a big difference.