Why is this being downvoted?
To elaborate: if, hypothetically, one's parent's income was a huge determining factor in one's education, and in turn one's education was the only relevant factor to one's income, then there would be a 100% correlation between one's education and one's income, and a statistically much smaller one between one's parent's income and one's education.
Although we see that strong correlation between education and income, we should evaluate the previous step through analyzing the correlation of parent's income to your education, not the correlation of parent's income to your income as that would be more indirect.
Please correct me if I'm missing something.