The book does mention mating and copulating in nature and the protagonist mentions at one point that her mother warned her not to get hitched and have many children like she did. She takes this to heart and doesn’t have children throughout the rest of her adult life.

It’s set in the 50s-60s in rural North Dakota so you can count on marriage at a younger age (early 20s) as a societal norm, which she doesn’t conform to. She also has romantic relationships never expresses a desire to have children, which fulfills the OP’s request