I'm a graphic designer. I've been out of the workforce for about a year, after giving birth to twins. I just had an interview for a promising position, but the interviewer kept asking me about my kids and my child care arrangements. I feel like I have to mention them, to explain that year-long gap in my resume, and I'm comfortable answering a polite question or two. But this interviewer was pushing hard on who cares for them, how I feel about returning to work, whether I think they are too young for full-time day care, and so on. I'm happy with my childcare situation: Between my spouse's flexible hours, my mother and mother-in-law living nearby, and quality day care in the neighborhood, I'm not concerned about how my kids will do. What concerns me is that I might have trouble getting a job because I'm a new mom. Is this legal?
It is not legal for an employer to make decisions based on stereotypes about men and women, including the very strong cultural assumption that women who have young children will be unable to devote themselves to their jobs. This is illegal sex discrimination. If you are turned down for the job because of it, you may well have a legal claim. To find out more, see Nolo's article on How to Start a Workplace Claim Against Your Employer.
When employers assume that women will have a hard time leaving their children, will not be fully dedicated to their jobs, or will be unwilling to travel or work long hours due to childcare responsibilities, they are engaging in sex discrimination. The difficult truth in our society is that, even as more dads choose to stay home with their kids, it's very rare for a man to face even a single polite question about his children, let alone an interrogation about where they are and how they can function when he is at work. It sounds like your interviewer has some pretty strong biases about working mothers -- and perhaps even about whether mothers should be working at all.
There are situations in which questions about child care might make sense, as long as they are gender-neutral. For example, an employer that offers telecommuting as a benefit might ask employees about any home-related responsibilities that might conflict with working from home, such as child care or elder care. However, the employer should not ask this question only of female employees, or assume that female employees with young children will be unable to focus on their work, even with child care arrangements worked out. For example, an employer who presumed that a female employee would spend too much time with her young children, even if she has in-home child care during her working hours, would be acting on a sex-based stereotype.