In my writersandcritters critique group, a number of different genres float about like flotsam in an open sea. We are not all mystery writers, nor are all of us romance writers. You'll not find every one of us writing significant and poignant poetry. We are an assorted group of women from around the world who write many different things.
While I enjoy reading the mystery novels a few are submitting, I would not attempt to write one. And I wouldn't try writing science fiction or horror or erotica. Simply because it isn't me. It's not within my comfort zone. That doesn't mean that I don't enjoy reading the submissions in those fields. Many times, I do.
I write fiction for kids, an occasioanl mainstream fiction story for grown'ups, essays, memoir and poetry as well as articles on the craft of writing. I write those things because I am comfortable with them, and that means I do a better job.
Think back to high school days when the English teacher assigned a 750 word science fiction story. Maybe there were 25 people in the class. How many of those 25 would be happy or comfortable in writing a science fiction story? Probably only a generous handful. What if the teacher had assigned a story in the horror genre? Or romance? Again, only some of the students would be proficient in that type of writing to come up with a genuinely good story. I would prefer that the teacher assign the story giving a list of several types that the student might choose from. They'll gravitate to the one that they feel comfortable with, the one that they would choose in reading material.
There are some writers who would tell you to move outside your comfort zone or you'll never grow as a writer. I can see the merit in that argument, but if I don't like horror stories, why in the world would I want to "grow" into them?
I believe that you will do a significantly better job when writing in your comfort zone. It may take you awhile to discover exactly what your own personal comfort zone is, but once you do, write and grow in it.