I believe that Jefferson would state that every generation can define marriage as they wish. In fact, I believe he would go further and state that it is none of our business how people 100 years from now want to define marriage. 
"On every question of construction (of the Constitution) let us carry ourselves back to the time when the Constitution was adopted, recollect the spirit of the debates, and instead of trying what meaning may be squeezed out of the text, or invented against it, conform to the probable one in which it was passed."
So I guess you've decided to try to debate Thomas Jefferson?
You will look long and hard before you find any provision in the constitution that states that the judiciary has greater power than other branches to interpret the constitution.
The notion of "Greater" or "Lesser" is a matter of perspective depending upon what you consider to be important. The fact that congress controls the money seems to me to be a very great power. That congress can impeach members of the court seems to me to make them of a higher power than the courts. That the executive controls the army, means the nation can launch a war that nobody wants against states attempting to gain independence from what they regard as tyranny. Again, a very great power. In fact, it was the ultimate power, because the President was arresting legislators and threatening to arrest Judges.
So all in all, even with the courts doing judicial review (and you didn't really answer who better should do it or why) they are still a poor third in terms of the power they wield.
It only looks like a lot nowadays because of the supine indulgent nature of the other two branches of government. Earl Warren should have been impeached, and so should many of the post Roosevelt appointed judges. Congress was just unconcerned with these Judicial breaches, and the Presidency was under the delusion that respect for Unconstitutional rulings by the courts should be given.
So I guess you've decided to try to debate Thomas Jefferson?No, I do not believe that I am debating Thomas Jefferson. I am quite certain that he believed that legislatures have the power to define marriage and I am quite certain that he would never have wanted to bind eternity to a static definition of any of our relationships. He would have opposed the Court's recent gay marriage decision because he did not believe, as many people believe, that courts should have the power to redefine marriage. Like him, I believe that legislatures should define these important relationships and that legislatures should determine when to change these definitions.
I also tend to agree with Jefferson about the role of the courts in interpreting the Constitution. As I said before, I do not believe that the Constitution provides the judiciary with greater power than other branches to interpret the Constitution. In the link that I gave you in my last post, Jefferson put it this way:
"The question whether the judges are invested with exclusive authority to decide on the constitutionality of a law has been heretofore a subject of consideration with me in the exercise of official duties. Certainly there is not a word in the Constitution which has given that power to them more than to the Executive or Legislative branches." - Thomas Jefferson
So all in all, even with the courts doing judicial review (and you didn't really answer who better should do it or why) they are still a poor third in terms of the power they wield.
Who should do judicial review? I think that everyone agrees that, by definition, courts should exercise judicial powers. That is why we call it the judicial branch. The disagreement concerns the proper scope of judicial powers.
There are many people who have bought into Marshall's argument that naturally the judicial branch should have the final say about "what the law is." As you can see from the quotes on that link that I gave you, Jefferson did not buy into that argument. And, I do not buy into that argument.
Unfortunately, most people have bought into Marshall's argument and that is why schoolchildren and adults are taught that the Supreme Court has the powers that it regularly exercises. Jefferson did not believe and I do not believe that the Supreme Court possesses the Constitutional power to decide that women have a constitutional right to abortion or that two men have a constitutional right to marry. Unfortunately, most people now accept the holding in Marbury and accept that it is part of the Court's job to find (create) such constitutional rights.
As I said in my last post, I believe that all three branches of the federal government have an obligation to determine the constitutionality of their conduct. I acknowledge, however, that the Supreme Court (beginning with the Marbury decision) has succeeded in convincing most people that the Court should have the final word because, well, just because. See, it is a court. They wear robes and who can deny that they are much better than everyone else at deciding things.
Jefferson did not let his anger about the Supreme Court's usurpation of power in Marbury wreck his life and I have not let my anger about it wreck my life. We just disagree with Marshall's opinion. Some people are very happy that unelected judges can create rights for people who cannot get legislatures to agree with them.
It is like everything else. I am unhappy with what the Court has been doing and other people are happy about it. But, life goes on. I take the bad with the good and I have to admit that I have been very lucky.