Help attack, humor jokes

One day, while Xiao Chen was at work, he received a phone call. After a few words, Xiao Chen hurried off. Xiao Chen: Manager! I want to ask for leave! My wife is going to have a baby. Manager: OK! You should go! So Xiao Chen left without saying anything, just like flying. Twenty minutes later, Xiao Chen came back, a little disheveled. When the manager saw him, he asked, "Why did you come back so soon?" A boy or a girl? Chen: I didn't know until ten months later ...