My job requires that I use splenic dendritic cells, harvested directly from the spleens of mice. The cells cannot be stored or cultured for any length of time because they mature and become useless very quickly. This means that every time I do an experiment involving splenic dendritic cells, a mouse must be killed, and its spleen harvested immediately.
I am already "exempt" from killing the mice myself - a co-worker does it for me. This was not always the case. At first, it was assumed that I was merely sentimental about rodents (on account of having them for pets) and that my discomfort would pass. (I am leaving my moral qualms with the use of animals for various human purposes out of this post.) Then, I proved myself utterly useless in the euthanasia process by crying so hard that a) I could not even SEE the mice through the tears and b) I had to keep taking off my surgical mask to blow my nose. Ok. So somebody else will do that job.
Now, I receive the spleens, which are approximately 1.5 cm, red, bean shaped organs, on ice immediately after they are harvested from the mouse. The spleens arrive with bits of connective tissue still attached. Before I begin to process the spleens (to extract the cells I need), I have to remove the little bits of fatty tissue. I do this with tweezers and surgical scissors. It takes about 5 minutes.
What has convinced me that I should never, EVER try to be a doctor is this: even though I've now processed more than a dozen spleens, I cannot get used to the sensation of pulling off the fatty tissue. I've always had a sense - unsubstantiated until now - that I would be unable to cut in to the skin of any organism, dead or alive. Many people have tried to convince me that performing surgery or autopsy or dissection is not as repulsive in actuality as it may seem in concept. This does not appear to be true for me. Every single time I clean those spleens it absolutely sickens me. I have no experience cutting any other kind of tissue, but something deep in my brain tells me that it FEELS WRONG. I just seem to have this built-in visceral knowledge that tissue is NOT SOMETHING YOU CUT, just like I have built-in knowledge that I should never break a bone on purpose, or never put my hand in a fire on purpose. I just can't get used to it.
Other people do not appear to have this mental block. This is a good thing, since if I ever need surgery I'd very much like to have a surgeon who is not freaking out. But man oh man... I'll leave doctoring to those with stronger stomachs than I.