The quote presented is from Mary Wollstonecraft's A Vindication of the Rights of Women. In this passage, Wollstonecraft examines assertions in Jean-Jacques Rousseau's Emile: Book V. Here is Wollstonecraft's quote with some additional context:
[For Rousseau] to give a sex to mind was not very consistent with the principles of a man who argued so warmly, and so well, for the immortality of the soul. But what a weak barrier is truth when it stands in the way of an hypothesis! [...] His ridiculous stories, which tend to prove that girls are naturally attentive to their persons, without laying any stress on daily example, are below contempt. And that a little miss should have such a correct taste as to neglect the pleasing amusement of making O's, merely because she perceived that it was an ungraceful attitude, should be selected with the anecdotes of the learned pig."
In Emile, Rousseau writes about a young woman who is given a lesson in penmanship but becomes upset when she sees that the O's she is writing are not pretty. Because they are not pretty, she decides she will not write any more. Rousseau contrasts the young girl's attitude with her brother's, who "was no fonder of writing" and disliked, in contrast to her, "the constraint, not the look of the thing." Rousseau's point is that girls, more than boys, are attracted to aesthetics, pretty things, and practical tasks like sewing, and by forcing them to learn the same subjects as boys at the same time as boys, life is made more difficult for them.
From one perspective—and certainly Wollstonecraft's—Rousseau's thesis is damaging to the philosophy of education, particularly that of women. In the outlined quote, Wollstonecraft argues that Rousseau gives no substantive reason for lumping all women into the same category as this particularly vain girl of his example. On the other hand, many pedagogical theories contain traces of Rousseau's ideas about differentiated learning, though not gender-based, to this day. In particular, both the Montessori and Waldorf methods encourage students to develop their natural interests. In addition, both have flexible guidelines for when a child should begin reading and writing. In Montessori, when students begin showing an interest in reading and writing, their interest is encouraged. In Waldorf, teachers discourage any active reading or writing instruction before age seven and do not require lessons in these subjects until as late as age nine.