Is it illegal? I'm not so sure. Technically a person can be payed any amount of money (if it isn't under minimum wage) for a job so long as they accept it and work there.

Ya this isn't illegal at all. No idea why #2's comment is up voted.

it depends on what they mean by underpaid... I would imagine paying less than your contract says you are entitled to is illegal. that's no different than me working a 30 hour week and only getting paid for 15, or getting contracted at 7.50 but them magically deciding they're gonna drop me to 6.0 an hour. that would sound illegal to me!

Not sure about the legality of what OP's boss is doing(I have no clue about California labor laws) but it is highly unethical

Well maybe not illegal but still really unfair. For example, If person 1 is in the same position as person 2 and person 2 gets paid even $5 more an hour than person 1 then it would be unfair if they were working there for the same amount of time. Some bosses are able to negotiate a raise though while others, like OP's father, can be dicks when it comes to their employees paycheck

I think there are a lot of employees that do the same job and get paid different amounts. One may be a better employee, or work more efficiently, or has worked there longer, or even be a male vs female (I hear a lot of women are still paid less than males even though they do the exact same job), or they could've just negotiated a better salary during their interview and sign on. I'm pretty sure there's nothing wrong with it as long as they're both getting the salary they've accepted on their contract. Plus, one may be more proactive in asking for raises and or taking on more work. You're not just paid for the job you do but for how you do the job. Plus I bet there are a lot of employees (especially in more lucrative positions) that have negotiated better salaries than the other employees. I think it's even more common in more lucrative positions.

If shes getting paid under minimum wage then it would be considered illegal And it also could be recognized as work place discrimination

They have their own job.

although not necessarily in this case, there are dads that are really professional and keep their work and personal lives separate, even if they own a family business. don't be too stereotypical about it

I don't see how he can get in trouble for underpaying an employee if the employee has agreed to that salary in their contract and is getting the amount promised. It might not be morally right, but I don't think he can get in trouble for it. Op agreed to that salary when he signed on. Now if he wasn't getting the amount that was stated in his contract than that's a different story. I'm not saying what his dad is doing is right, I'm just saying that it's not illegal or wrong in the sense that he can get in trouble by anyone for it. Unfortunately it sounds like op agreed to that salary in the first place. Op, either search for another job where you get paid more, or prove yourself to your dad by working hard and then ask for a raise since he's been underpaying you; tell him that you think you've proven that you're worth more.

how is getting ripped off by people you love and are supposed to love you the bright side?

Depends on how old OP is. If OP is 18+, child labor laws won't mean squat. If OP is under 18, then child labor laws come into play