I must disagree, sir. She is looking for a one night lover. Not an 18 year responsibility.
1) The warning in the song states She’s going to get you, All that she wants is another baby.
She is after you, you being the target of her efforts. The baby that is all that she wants is you. If she were after offspring then the warning would state She’s going to get your manseed.
2) It’s a night for passion
If the objective or her pursuit was a child then this line would provide irrelevant information. If what she really wants is a child irrespective of the role of a male counterpart in the raising of said child and if this man was a disposable seed bank then why would the passion or lack-their-of be important to the message? Passion is only relevant if her goal is to have a passionate night with the man.
3) Beware of what is flashing in her eye
If she is after manseed shouldn’t the twinkle be in his eyes?
4) She’s a hunter you’re the fox
A hunter pursues a fox because getting the fox is his/her goal. If she were after the man for what he could do for her then a more appropriate analogy would have been She’s a farmer you’re the guano producing bat or She’s a thief you’re the egg laying chicken. The Fox (i.e. you) are the subject or her desire. She is not more interested in what you can give her that will have greater long term value to her.
5) When she woke up late in the morning
Light and the day had just begun
She opened up her eyes and thought
O what a morning
Its not a day for work
Its a day for catching tan
Just laying on the beach and having fun
We can tell from this description of her thoughts on the day in question that she likes a) sleeping in, b) skipping work/responsibilities c) going to the beach and having fun. If we consider the hypothetical scenario that she has had a baby (offspring) before then clearly she must know that a baby is a large responsibility and that visiting the beach and sleeping in will no longer be options in her life.