Whether you've recently tied the knot or you're simply creeping toward 30, you've been asked—perhaps on repeat—whether you want children. And if you've responded with a resounding no, new research shows you're in good company. In fact, according to the Cassandra Report: Ages and Stages, one-third of millennials don't want to be mothers.

Of the 75 million millennials, about 25 million don't have a desire to have children—compared, the report shows, to 22 million Generation Y men and women who already have kids. And whether they want children or not, millennials aren't worried about what people think: 69 percent believe there is no longer a societal stigma associated with not wanting to have children.

Says Cassandra global president Joe Kessler, "Priorities shift as people mature, but millennials continue to go off-road' in terms of what's expected of them. Their attitudes toward the prospect of becoming parents are indicative of their desire to construct their own personal paths to happiness."

The top reasons millennials cite for not wanting children, the report shows, revolve around their lifestyle: 34 percent don't want to give up their flexibility, they say, while 32 percent don't want to take on the responsibility.

Additionally, if they have children, millennials say, they don't think they need to do so within the confines of marriage. Unlike their baby-boomer and Generation X parents, 75 of millennials surveyed say it's acceptable to have kids before getting married, the report shows.

"Our notion of the conventional family unit is going by the wayside," Kessler noted in a statement.

Do you want children? If not, do you agree with other millennials about why not?