Gender disappointment is a term that has been coined through people's (typically women's) online shared experiences of sadness at having a baby who is of the opposite sex to the one they imagined having. For some people, there is no particular preference for the sex of their child. But for many people, their preference for a child of a particular sex, is steeped in deep meaning, past experiences, hopes and dreams.
When the sex of one's baby is determined in pregnancy, or after birth, there can be feelings of disappointment, sadness, grief, and for some people, devastation, upon finding out their baby is not what they had hoped for.
People move through their feelings of disappointment in different ways and over different time periods. Bonding with the child who is coming/born may or may not be affected by feelings of disappointment. Counselling can be helpful to work through these feelings, and to explore the assumptions that might underly feelings of disappointment and grief.
"Gender disappointment: Grieving the idealised child". Article by Dr Renée Miller
"Gender disappointment in new and expectant mothers" Article by Grace Jennings Edquist