Occasionally, I come across the term “designer baby,” and I am reminded that some parents now have the option to screen or modify the genes of their unborn children to ensure or avoid certain traits. It always gives me a feeling of unease. Obviously, I did not take this route — partly because, at least with my son, I never had to actually make the decision. My third child, Eliza, was a late midlife accident. I chose to have her despite the possibility she would have XLH, but would I have made the same decision in a planned pregnancy or if given a choice much earlier in the process? I can’t help suspecting that because of advances in genetic mapping, genetic testing, the sheer range of prenatal choices, chances are that in a generation or two, there will be no one in the world who has XLH, no one who looks like me or my children — at least not in the so-called developed world — and I don’t know how to feel about that.

I am aware that some studies do show that short people score less points on “happiness scales,” whatever they may mean, but we are not the average study subjects. We are ourselves, individuals; we are what we are — short and proud of it. We are people with a disability.

Sometimes people stop us and ask us what is wrong with us; most of the time I can see that people notice, but they don’t say anything. Walker is more visibly disabled, which makes Eliza feel bad. She says sometimes she feels like a fraud because she has the same thing, but in her case “you almost can’t tell.” Walker rides a bicycle. Eliza does yoga. Both of them pursue these physical activities with fierce and single-minded passion. Both do so because there are other physical activities — walking, running — that they cannot pursue without difficulty. (Oddly, my least athletic child is my oldest, Annabelle, who regularly proclaims she hates all sports.)

Pain — both physical and psychic — is a part of my two younger kids’ daily experience, and it is the part that is hardest for me to get over. Perhaps this is what my relative meant. Perhaps sparing your loved one that psychic pain is the reason some people give their short-statured but otherwise perfectly healthy children human growth hormone, so they may grow just a few inches taller.

Most of the time I believe my children will transcend the parts of their disability that might make them suffer. Walker may be only five feet tall, but he is in every conceivable way an engaging personality. He has friends, wild schemes for the future, a wicked, deadpan sense of humor. Eliza is all darting motion — ups and downs. She sings in the shower; does cartwheels on the lawn. She also struggles with an eating disorder and anxiety. And Walker, normally even-keeled, occasionally gives in to fits of rage and frustration when, tired of the effort of simply moving through a day, or being left out at school, he punches walls, rides his bicycle too fast.

How much of this can I really blame XLH for? My oldest, Annabelle, would not say she has a perfect life. At 23, she is floundering a little — unsure what to do with her life or how. She adopts stray dogs. She gets tattoos. She works in a supermarket bakery and is struggling to finish college. She writes killer poems that are also very angsty.

Sure XLH has a cost, but so does life.

I know what the “designer baby” people would say: the more “advantages” — beauty, height, intelligence — the better the life chances, the better the life. But I am not sure I believe them.