While Yitzchak and Rivka both prayed, in opposite corners of the room, to be blessed with a child, it was Yitzchak's tefillos (prayers) which were answered over Rivka's. On the verse "and Hashem responded to his pleas", Rashi comments that there is no comparison between the prayers of a tzaddik ben tzaddik (righteous person who is the son of a righteous person), and a tzaddik ben rasha (righteous person who is the son of a wicked person). In this case, because Yitzchak was the son of Avraham, his prayers were accepted over those of his wife's, who was the daughter of the wicked Besuel.
"Hmmm," I mused to my husband. "You know how there are some people who refuse to date ba'alei teshuvah (returnees to Judaism), or geirim (converts) because their background is perhaps not as spiritually sanctified? Well, doesn't this Rashi imply that there is basis for this objection?"
As I wrote above, I have always taken issue with this attitude, for a variety of reasons, all of which I am too tired to present here. But I wondered if perhaps I'd been wrong all this time. (Happens occasionally)
To which my husband replied...
"Uh, Riva...Yitzchak MARRIED Rivka!" :-)
He's clever, no?