As many of you who are UK resisdents are probably aware, the National Blood Service in the UK, a fine organization which does in many respects a wonderful job, has one major stain on its record: it does not allow gay and bisexual men to donate if they have ever had sex. Whether oral or anal, whether it was yesterday or a decade ago, if you are a man and you've had sex with another man you can never give blood again.
This ridiculous and discriminatory policy is plainly visible in their blood donation test, specifically this question. They weasel out of this policy being discrimination by claiming it is "behaviour based" (hence the question about sex acts rather than strictly sexuality). But it doesn't bear any scrutiny: why should the gender of the person you have sex with affect the dangerousness of that act? Their explanation of their policies does nothing to explain.
So now you have the capability to sign an electronic petition asking the Prime Minister to overturn the ban. The petition is hosted by Number 10 itself, so you can be sure they're really listening.