It's not the best source obviously, but according to Wikipedia this is incorrect, women can be charged with rape (if I've read this correctly):
Under section 1 of the Sexual Offences Act 2003, the use of the phrase "his penis" is a misnomer as all laws were previously written using male pronouns. It does not exclude those who are legally female from being able to be covered from the definition of rape.[12]
The last time I pasted a Wikipedia link on a world news community I was banned, so mods please just delete this comment if I've done something wrong. [Edit] note it was a different world news community, I'm just trying to be extra careful.