I personally don't have a problem with it.
Plenty of people do various things to try and up their chances of a child of a particular gender - Shettles method for example - does that make them bad parents?
Many, many parents do have a preference - doesn't mean they reject their baby if it turns out to be the other. I had a preference for a girl, DH didn't mind. I was convinced I was having a boy and when they said girl at the scan I was almost momentarily disappointed I'd got so used to the idea of a boy.
My IL's have 4 boys - I know FIL would have loved a daughter... instead he's now got 7 grand-daughters and not a single grand-son. I know my MIL worries about saying the wrong things to her DILs (she never does - she's the MIL of one's dreams) and admits it would have been nice to have had a daughter although she adores all her sons.
The Ingender Forum, has many women who go there to deal with their gender disappointment in a safe space.
I have several friends who have struggled with coming to terms with their family only having children of a certain gender - they don't love their existing children any less, they just feel that they wouldn't have another if they couldn't guarantee the gender.
One friend lost her daughter very tragically at 39 weeks - she's since had 2 little boys, but openly admits that she would have loved another little girl. Not to 'replace' the child who died, but because she had certain dreams and hoped for a relationship like her own with her own mother.
Obviously children come with their own personalities and you can guarantee nothing. I was a total tomboy and have got a pink princess who likes all the toys that I would have hated as a child, but I rather enjoy indulging her!
Many parents hope for eventual grandchildren and their children decide not to have any - doesn't make it wrong for their parents to have that desire though.