My daughter (then 5 and already the sister of a younger brother) dearly hoped for a girl when I was pregnant again - we did not want to know, but she prepared everything for her "little baby sister" that we decided to find out after all, just to avoid disappointment. Surely enough, it was a boy. She was inconsolable, it was for her like her sister died, she had so many little ideas and plans and now they didn't happen (14 years later: she loves her brother dearly, so no problem). If we had revealed the gender and recorded her reaction - it would have hurt her brother for sure.
My parents first baby (a boy) died. When my mom got pregnant again (with me) both grandfathers (both running small businesses) were convinced that it would be another boy and both were very disappointed when I was a girl. This story was told over and over again ... it hurt me immensely as a child and I felt "wrong" and like I had let them down.
I had an older brother.. he didnít live long... I never knew until I was an adult... it was something not talked about. By the time I arrived one grandfather had passed away and I think the family was happy for a child.