What are we hiding from?

I found myself in conversation today with my new manager. Well, I have been at the job almost 3 months, so he's a semi-new manager. As we spoke about things to come in the department and each of our expectations of the future I kept finding that I was very conscious NOT to mention ever having another child. In my past experience with one manager in particular, who was a woman, she actually would out loud make it known she did not want to promote the women she thought may get pregnant. As a result I am very careful not to tell managers how much I love being a mom and spending time with my son. If I have to work, I certainly do not want to be looked over for promotions and raises. I find it crazy that I have been called "rock star" by more than one HR personel, I have a Master's Degree and glowing references, yet I need to hide the fact that I may want more children. What a message to send the young folks of today.