My friend's niece was born extremely premature, like as-early-as-a-child-can-possibly-survive premature. It's been very hard for their family and they won't know until they watch her develop for awhile what the implications of this are. There is only one at this point: The child is impossibly small at 4 months old (she'd barely be born by now) and looks like an alien. I know, it's cruel, it's horrible, but she looks like little more than a foetus in clothes. She shows off the pictures of her tiny little niece and she totally creeps me out.
She already has a lot of health problems and it's likely they will continue. It's not just the likelihood of health issues either; it's even more likely that she will have developmental and mental problems.
Now, add this to the fact that my friend's sister was knocked up -- this was a very unplanned pregnancy. She and her now-husband (they wanted to "do the right thing") are incredibly young, don't have the kind of money or, quite frankly, the maturity (from the stories I've heard) to deal with this.
One of my greatest fears is having a sick child. I know it's possible to lead a fun, social life and career with a child, but what about a sick child? Something as minor and prevalent as ADHD, to something as major as Down Syndrome or worse... there goes your life. You're not even Mom anymore, you're Caregiver, in some cases stuck with a baby who is still, functionally, a baby at 30. A woman and her Down Syndrome son joined us in the elevator at my grandmother-in-law's building, and my husband and I smiled at each other and we knew why.
Our friends and family are blessed with children whose worst issues are behavioral problems (specifically, our nephew who has a sensory disorder and my cousin who has a learning disability). My husband is *obsessed* with the law of averages and is convinced that one of the next babies who comes into our life will have a major issue. Even if that is a little extreme, I know I definitely don't want to be a part of that club. It's a chance I don't want to take.