My youngest daughter is pregnant.She wanted a maternity shirt that said incubating so I found a site online that let me design her own shirt so I had one made that says incubating with a chick on it and at the bottom it says hatching in November. Yesterday we went for the first ultrasound to confirm due date. I am amazed at how the technology has changed since she was born 26 years ago. The tech was going through all the different areas explalining what each was. She shows us the gestational sack(placenta) then she says here is your yolk sack. My daughter and I starting laughing and I said to her " see I told you that you were going to hatch" The tech looked at us like we were crazy. I then explained we had chickens. Crazy I never knew that a human baby had a yolk sack.