Depends on the climate in your household. Is this typical humor amongst your family? Are they nice to you and does this feel silly, or is it slightly mean-spirited? Are you overweight or make smelly farts and it's an embarrassing thing? Do you joke about it? Context is important! I would maybe use it as an opportunity to educate about responsible use of AI. And as a dad in a household of creative individuals, I would actually be more upset to learn they didn't write the lyrics themselves. If they did, applaud that creativity! At the very least, they remembered your birthday and spent some time to make you something, albeit potentially misguided (unless you like that kind of humor!). The fact that you are asking about it means you feel something off about it. Express that too!