If you took offense to that then you are apparently very easily offended....
If you don't have a relationship established then it is not kidnapping from a legal perspective. I understand that it probably seems like a sort of Catch-22 in your eyes, but it is what it is.
The best way to avoid such a scenario happening to you (unlikely as it may be) is to not engage in casual sex, use birth control such as a condom/spermicide every time you have sex and if you do decide to have children, do so inside a committed relationship such as marriage, where your legal paternity rights are firmly established.