她希望自己的宝宝是个女孩 用英语表达

对这句话,可有两种理解,即未出生的宝宝 和 已出生的宝宝。所以,根据情景或上下文可分别译成：She wishes that her would-be-born baby would be a girl。
She wishes that her baby were a girl。(事实上不是女孩)
希望对你有所帮助。