This statement, coupled with the subject header of the post, tells me this is going to be an interesting thread.
Even if she were truthful about using an IUD, no method of artificial birth control is 100% effective.
Not really sure I understand the question. When you choose to have sex, you choose the consequences of doing so, one of which is the possibility -- no matter how remote -- that a pregnancy might result. If your paternity is established, you'll have the right to seek custody or visitation, and the noncustodial parent will have the obligation to pay child support.
How does you willingly having sex equate to being "tricked into paying child support"?

