“Child-free” is a newish popular term among culturally liberal millennials, which means it will probably enter the Associated Press Stylebook and Merriam-Webster soon enough. It’s replacing “childless” for reasons explained by Rhiannon Lucy Cosslett, a columnist for the Guardian:

Yes, language is always loaded with subterranean meaning and subtle connotations. Yes, parenthood, fertility, singlehood, and nulliparity are all sensitive topics fraught with personal, medical, and emotional baggage. But also, having children is the ordinary way of modern civilization for generations and the only way of creating new generations. This is true even if it upsets some Guardian readers.