"How can my son not be straight after all I've said and done for him?"

This quote by Rod Stewart is likely describing the concept of parenting and the expectations that come with it. The speaker is expressing their confusion and aggravation at their child not living up to their expectations, in spite of all the effort they have actually put into raising him. It could be analyzed as a reflection on the difficulty of parenting, and the awareness that regardless of all the love and guidance a moms and dad can provide, a kid's choices and choices are ultimately their own. It might also be translated as a commentary on the concept of gender roles and expectations, and the speaker's confusion at their kid not adhering to the traditional gender roles they have actually been taught. Eventually, this quote is a reflection on the intricacies of parenting and the awareness that a parent's influence is not always sufficient to shape a child's decisions.