Less than a day into her tenure as leader of New Zealand’s opposition, Jacinda Ardern was twice asked to explain her decision on whether to have children, a personal question she said none of her male colleagues would have to answer.

Ms. Ardern, 37, said she was willing to answer questions about how she balanced work and family life, an issue she has spoken about publicly in the past, but said on Wednesday, “In this day and age, that doesn’t mean that any other woman should be open to those questions.”

In two interviews in 24 hours with New Zealand news outlets, Ms. Arden defended the rights of women to work without speculation over their personal decision to have children, or not. Her reactions to the men interviewing her enlivened the public debate over the double standards faced by men and women in the workplace.