Our people are trained that if someone does start to talk about their family during an interview, they are to try to change the subject as quickly as possible because of the laws and potential for bias. EVEN if they volunteer the information.
My department is a family friendly department. They also fully believe in using all of your CTO (Combined Time Off). Since it's a sick/vacation bank combined, everybody has their time and can use their time. It's to your advantage to not have to call in last minute because everybody would rather use their time as planned time off. As long as you notify your supervisor more than an hour in advance of your start time, it is considered planned. So, if I email my boss at 6:30 am (with an 8:00 am start time) to let him know I won't be in, it's planned time off. Not a bad gig, I must say