B'reshis chapter 46 lists the seventy descendants of Yaakov who went to Egypt. It actually lists sixty-nine: let's assume Yocheved was the seventieth, as Rashi explains. It also lists (in pasuk 12) two who died before the trip down, so there are a total of 72 descendants of Yaakov listed. Of these, three are female: Yocheved, Serach, and Dina. Assuming a 50% chance of having a boy at each birth, the probability of such a disproportionate number of babies of one sex is about 0.000000000000003%. What's going on?
(And if you want to say there were females not listed (besides Yocheved), then you have to explain why the Torah says there were seventy (do the females not count?) and why it lists some females and not others. That's even if, as suggested in an answer, there are dead females not listed: the Torah lists dead males, after all.)