most births outside marriage

I read the article "For Woman Under 30, Most Births Occur Outside Marriage" by Jason Deparle and Sabrina Tavernise. it was obviously about how more children are born to unmarried parents under the age of 30. i know there are multiple reasons for this. for example, some pregnancies are unplanned like if you don't use condoms or are not on any type of birth control and you are not married it is likely to happen. Also, some women might not be ready to marry like my biological mother she says she don't wanna marry because she does not want to be responsible for anybody else i think she is just selfish because although she just turned 32, she has 4 kids and 3 different fathers to her children and she has not been married yet. also my friend's aunt got 6 kids, 5 different fathers to her children and still is not married, although she wants to marry she did not yet. i just do not think that this should be an issue because what you do with your body, your time and your life is your business. sometimes people don't want to get married for several reasons like also a lady in the article said that if she would have married her baby's father it would have been like raising 2 kids. but there is also people who want to be married and wont have sex or a child without a ring on their finger, even though there is not that many people who do that now and days.