It may be shocking for you to hear, but...well, some people don't like Amy Pond. (Yes, I know. Take as much time as you need to wrap your head around that idea and then join me at the next sentence.) Despite being a great companion, possibly the best so far in the new Doctor Who series (and cue flamewars in three, two, one...) some people really can't stand her. They say that she's just one more example of why they consider Moffat to be a sexist writer. Amy Pond, according to them, is a stereotypical female character of the worst order, a misogynist caricature of real women that Moffat created as an object of fanboy lust, nothing more.
Is it true? Let's look at Amy. She's clearly not a passive character, which is always one of the big red flags for sexism. Amy makes her own decision to travel in the TARDIS, and she is determined not to give up on it; she's been inadvertently gaslighted for most of her life, being told that the Doctor was just an imaginary friend that it's past time for her to give up on, but she hasn't stopped believing in him for a moment. (And she's avoided winding up in a mental institution despite all that, which indicates that she's socially and emotionally well-adjusted despite dealing with issues that would have sent a lot of people into a rubber room.) She acts as more than just a passenger in the TARDIS, making decisions on matters from space whale survival to whether her husband will get to travel along.
And speaking of her husband...anyone who is trying to claim that Amy is sexist will have to deal with "Mrs. Pond". Amy is very clearly the decision-maker in that relationship, and it is not depicted as dysfunctional or shameful. Rory is not henpecked, he is in awe of his wife's determination and he respects her decision-making ability. While he is always there to reinforce her when she needs it, he does not try to enforce a patriarchal authority over her, because he loves her for who she is and that includes her forcefulness. Amy and Rory's relationship is just about the least sexist, most well-adjusted relationship in any genre series ever.
And Moffat has never put Amy into sexual peril; unlike, say, Peri, the villains do not lust after her body and want to keep her as a trophy bride. Amy gets put into her share of danger, just like the Doctor and the other companions, but it's not represented as specifically due to her gender. (Arguably, she is not a capable fighter, which is apparently a prerequisite for "strong female characters" these days, but neither is anyone else in the series, with the possible exceptions of Ian, Leela, and River Song.)
No, the main reason I think people call Amy "sexist" is...well...not to put to fine a point on it, but she has sex. And she enjoys it. Amy has been known to talk about sex, to ogle men she finds attractive, to ogle women she finds attractive, and to even have enough of a hint of kinkiness to enjoy dressing up in costumes. In short, Amy Pond has genitals and isn't ashamed to say she enjoys using them. To some people, this immediately makes her a terrible slut unworthy of inclusion in the same genre as decent women.
Think I'm exaggerating? Go look at the recaps on TV Without Pity. (Can't link to the site from work, but you should be able to find it with the help of Google.) Until his head exploded from having to talk about women who actually admit to enjoying orgasms, Jacob the recapper inserted constant comments about how Amy's career as a kiss-o-gram showed how damaged she was as a person, and how the Doctor wrecked her by coming into her life and leaving and now all she does is have emotionless flings in order to make money. As a KISS-O-GRAM. God alone knows what he would have said if she'd thrown hugs into the deal.
There is, at heart, a fundamental belief that women who have sex for anything other than procreational purposes are bad. This has been dressed up in countless other beliefs over the eons, and the claim that feminists should be prudes is just one more disguise for it. This doesn't mean that there's no such thing as exploitative sexualization or titillation; of course there is. But a female character shouldn't have to wear a burqa in order to be free of criticism for her feminist credibility, and it's frustrating to see people try to pass off their slut shaming as feminism.
And that doesn't even get into River Song...