Au contraire.
The Supreme Court, in the Roe v Wade decision, interpreted the term “person,” as used in the 14th Amendment, to not include a fetus. Whether this interpretation is correct or not is beside the point, they did make that interpretation.
So for Congress to pass a law specifying that the fetus IS a “person” protected by the 14th Amendment, it would necessarily involve Congress overruling the SCOTUS interpretation and substituting its own. Which, as I said, the Constitution does not give them the power to do.
The whole discussion is moot, of course, since Congress will pass no such law, not even the House.
Once again your premise is 100% wrong. Roe v Wade did not interpret anything existing in the Constitution leading to their decision.
Roe v Wade: FULL Text (The Decision that wiped out an entire Generation 33 years ago today - 2006)
Your premise that Congress can't pass a law that overrules a prior SCOTUS interpretation of the Constitution is also 100% wrong. And utterly ridiculous.