.ס The Switcheroo

ואחר ילדה בת ותקרא את שמה דינה מאי ואחר אמר רב לאחר שדנה לאה דין בעצמה ואמרה י"ב שבטים עתידין לצאת מיעקב ששה יצאו ממני וארבעה מן השפחות הרי עשרה אם זה זכר לא תהא אחותי רחל כאחת השפחות מיד נהפכה לבת שנא' ותקרא את שמה דינה

There is some discussion in the ספרי אגדה as to what exact נס transpired here. רש"י in ויצא, whose source is פרקי דר' אליעזר, seems to imply that the fetus was simply switched from a male to a female, as our גמרא would seem to indicate. However, תרגום (המיוחס ל)יונתן בן עוזיאל, explains that דינה and יוסף switched wombs.

Here is an old וישב shtikle on the topic and the possible conflation of these two accounts:

The parsha begins with a description of the life that Yosef lead and the relationship he had with his brothers. Rashi (37:2) comments on the words "vehu na'ar," that Yosef had some tendencies like those of na'aros, young girls. He would comb is hair and beautify himself.

Rashi (30:21) in explaining the reasoning behind Dena's name, writes that the fetus was initially a male in Leah's womb and she prayed to give birth to a female so that Rachel would not have less males than the maidservants. The fetus subsequently turned into a female. Targum Yonasan writes that at the same time, Rachel was pregnant with Dena and Yosef was in Leah's womb. The fetuses switched wombs. Dena was born to Leah and Yosef to Rachel instead of the reverse. The source for Rashi is in Pirkei d'Rabbi Eliezer. Radal comments there that this is why we see some male tendencies in Dena, that she "went out" and explored in Shechem

R' Yaakov Kamenetsky, in Emes l'Yaakov takes this one step one further. He writes that this is also why we find female-like tendencies in Yosef. This suggestion troubled me greatly. First, Rashi does not seem to hold like Targum Yonasan*. According to Rashi, Yosef really had nothing to do with the whole Dena episode. And even according to Targum Yonasan, there is no switching of gender at all but rather the fetuses switched wombs. Even Radal's suggestion does not fit with Targum Yonasan, let alone R' Yaakov's.

*Incidentally, רש"י's approach is problematic with his commentary to פרשת וישב מ"ו:ט"ו where he explains the attribution of the boys to their mothers and daughter to her father with our later גמרא of 'איש מזריע תחילה וכו. The מהרש"א answers the difficulty in רש"י with the תרגום יונתן.