Is dating a younger guy illegal?

California – The age of consent in California is 18. It is illegal for anyone to engage in sexual intercourse with a minor (someone under the age of 18), unless they are that persons spouse. California employs a tiered system where the greater the difference in age, the greater the penalty.

Can a 13 year old and 15 year old date?

If dating includes sex (or any form of sexual activity) then the answer is NO - and parental approval is irrelevant. If you are under 16 then you may not lawfully engage in any sexual activity (not just intercourse) with anyone.