From The Commentators' Seder: A companion volume to The Commentators' Haggadah including additional inspiring halachic insights and homilies, by Rabbi Yitzchak Sender:
"The story of the Exodus must be recited in response to questions. This was mandated by our Sages based on the pasukim which state, 'and you shall tell it to your son'; והגדת לבנך, and similarly, 'and when your son will ask': והיה כי ישאלך בנך. . .
"The question then arises, what about a daughter? Is she permitted or even obligated to ask? . . . The opinion of the Aruch HaShulchan. . . is that a daughter is allowed to pose questions on the Seder Night, but only if there is not a son present.
"Related to this halachic principle of בן קודם לבת, a son taking precedence over a daughter, there is an inspiring story which I heard from Ha Gaon Rav Moshe Hershler, of blessed memory. As the boat which was carrying Rav Yisrael of Sklov, that eminent student of the Vilna Gaon, neared the shores of Eretz Yisrael, a violent storm arose and the boat sank. Rav Yisrael, who was traveling with his small son and daughter, proceeded to grab them each under one arm and swim to shore. Because of the strong current, he soon realized that he would not make it to shore unless he released one of the children and had one hand free with which to battle the waves. Turning to his daughter, he explained to her, with a broken heart, that the halacha required that she be the one he must release (based on the Mishnah in the last chapter of מסכת הוריות, where it is clearly stated that saving a son takes precedence over saving a daughter, because a son is obligated to fulfil mitzvos and a daughter is not). His small daughter replied to her father as follows: 'If that is the halacha, so be it, dear Father.' She then proceeded to grab her father's beard and hang on to it tightly with all her might, refusing to release her hold. Explaining to her puzzled father why she was doing this she said: 'Your halacha says: בן קודם לבת, and this is what you must do; but my halacha is different, it tells me: וחי בהם: the mitzvos were given to live by, and I must do everything I can to preserve my life.' As she was speaking the storm suddenly subsided, and Rav Yisrael was able to wade to shore safely with both children under his arms.
"Rav Hershler concluded this story by saying that when it was told to Rav Yehezkiel Abramsky, tears welled up in his eyes and he remarked; 'Ribbono Shel Olam, how great are your people that a father could say to his beloved daughter with such unswerving faith that this is the halacha; and that a daughter could reply with such loving acceptance and could display such genius in applying the halacha so appropriately to her own situation!'"