What do you think, is the society around us expecting everyone to have children?
I've been wondering this because I don't want to have children. I don't think I have ever had the dream of having children of my own and over the recent years even less after being diagnosed with MS, I just couldn't handle it. I'm 37 years old, might be too "late" anyway.... Biologically it might be possible but I don't think I want to start up a family at this age nor later. When I was in my early 20s I remember thinking that the only reason to get into a relationship was sex. It's still true today.
I do have about 2 and a half year old goddaughter and I think she's enough for me.

After spending time with her with this disease I don't think I could handle all that goes into taking care of a child.
I started to think about this after reading something from the web, a Finnish 33 year old woman didn't want to have kids and some people apparently had asked her "what's wrong with you?"
My sympathies. I'm 20 years older than you, and I know all too well what it's like to be asked that question: "What's wrong with you?" when I told my old high school or junior high classmates that I didn't have kids, and had never wanted them. My generation, even more than yours, was simply expected to marry and have kids. It was taken for granted, and some of my female classmates got married right out of high school.
I know I don't have the temperament for young children. I can tolerate older kids in numbers of maybe one or two at a time, which is why it's a very good thing I didn't carry on with plans to become an elementary school teacher (thankfully realizing this about myself during my first year rather than later). Even as a teenage babysitter, I concluded that I didn't like babies and decided that any kids I babysat would be "housebroken and able to communicate clearly" - I'd had too many instances of not knowing wtf the kid wanted and they were too young to tell me. So... about age 4. No younger.
Like you, I have a medical situation that makes having children unwise, even if it were possible. I remember when I was just a little older than you (late 30s, coming up on 40), having an argument with my mother. She was determined to be a grandmother, she kept saying, and wouldn't listen to my explanations that I wasn't in a relationship at the time, was certainly not thinking of marriage, and she asked, "What about that boy you were seeing in high school, you're still friends..."... Honestly, any guy off the street would have been okay by her, and marriage was optional. All she wanted was a grandchild.
So I picked up one of the cats I had at the time, one who had been adopted at such a young age that he imprinted on me and really did consider me the next best thing to a real cat mother. I held him up, and told her, "This is your grandcat. He is the only grandchild you will ever have."
I guess she finally got it. The following spring, when May rolled around, she wished me Happy Mother's Day.
So if you have any pets, just say those are your kids (by adoption). Adoption is a valid thing, and if anyone mocks you for what species they are, that says more about them (the human) than about you. Some people have told me I'd have made a good mother, I thank them for the compliment, but I know the truth. I'm a very good cat guardian (have had cats for nearly 44 years, all ages from birth to death, several have considered me "mom"), but human children aren't in the picture, I don't consider that to be something I owe the world (either children or an explanation), and all you owe people is what you yourself decide to say... which could be anything or nothing. The choice is yours, and whatever you decide is right for you is right.
So if anyone berates you for not having reproduced (someone on a gaming forum was irritated that I'd "deprived the world" of any offspring), the fact is that it's your business, and not theirs. Your body, your life, your choice.