When you apply for a visa to visit the UK, one of the main things they want to see is evidence that you are genuinely planning to visit (i.e. you're not pretending to plan a visit but actually intending to stay forever). As such, they ask for evidence that you have a reason to leave at the end of your trip, generally in the form of proving close ties to your home country.
Evidence of family members remaining in your home country is an example of evidence you can provide to show those ties, it is not mandatory. If you don't have family members remaining in your home country, you don't have to provide evidence of having them (and as you don't live in India, your parents being there wouldn't be good evidence of what they want to see anyway).
This is not a problem, and does not mean mean you can't get the visa. It just means you'll have to show something else to demonstrate that you're not likely to overstay your visa. As you live in the US, this probably means reasons to return to the US. Your F1 visa, along with evidence that you are enrolled in a suitable programme of study, should be a very good start. Additional possibilities could be evidence of any spouse, children, or other relatives you may have in the US, or any businesses or properties you're involved in.