Is a woman considered to be less of a woman if she doesn’t have children or doesnt marry?

Why are single women looked upon so negatively by being referred to as “spinsters”?

Is a woman who experiences motherhood seen as more deserving and a more complete woman than one who doesn’t/can’t become a mother?

Why doesnt the same attitude prevail towards men who find themselves through choice or circumstance stripped of fatherhood or being a husband?