Of course you're not unreasonable to feel that. Many people will have an idealised idea of what their families will look like before they have any children and it's natural to feel a bit disappointed if that doesn't materialise. It's only a problem if you obsess or if you feel disappointed with the children you have.
I was always a bit ambivalent about having kids but decided to go for it. I would have preferred a girl as I only have nieces and felt more familiar with girls but ended up pregnant with a boy. I ended up terminating at 22 weeks due to ffa.
Next pregnancy, I also would have preferred a girl but had a boy. He's very independent and, while we have a great relationship, he was never a mummy's boy.
Next pregnancy, I thought a boy would be a better option as I felt two boys would be more likely to get on. I had a girl. She and her brother are very different people and only really started getting on in their late teens. She and I also have a very good relationship but I probably have more in common with her than with her older brother.
Next pregnancy, my preference was for another girl as again, I thought 2 girls might get on better. It was another boy. However, he and his sister always got on really well when they were younger. They've drifted a bit over the last few years but I think that is more that they are at different stages of their lives. He's a total mummy's boy, while still being pretty independent.
So basically, I got both sexes. All three are very different. I have excellent, but different, relationships with all three. I am glad I have a girl as if I had all boys, I know I would be left wondering and vice versa.
Oh, and neither of my boys piss on the toilet seat. They were trained properly from a young age.
Ignore the posts saying you're unreasonable because some people can't have children. You are entitled to feel what you feel. Nobody would tell someone with a broken leg that they shouldn't feel hard done by just because some people are permanently in a wheelchair.