This is in response to this video on Think Atheist: http://bit.ly/icTg8g
Right off the bat they make a classic argument from ignorance (how did you get here, very ignorant question given current levels of scientific understandings of physics, chemistry, abiogenesis and evolution) and they fail to discuss these very well-known scientific answers so they are flat out lying to people.
They then go to the Special Pleading for God because the universe couldn't have come from nothing (but God apparently can).
"No basis for right or wrong" is an unsupported position. We clearly do and since they cannot claim any knowledge coming from an actual "god" this is not a valid argument.
Cancer risk has NOTHING to do with being gay (correlation is not causation). Not all gay people engage in anal intercourse and many straight people do. Furthermore, it has more to do with viral and bacterial risks (ever heard of a condom?)
And it completely IGNORES the heterosexual risk factors associated with biblically sanctioned sexual activity even between completely monogamous partners. In biblical times ANAL sex would have been VASTLY safer than vaginal sex due to risk of death due to pregnancy (it's not as bad now thanks to modern medicine but even today pregnancy carries some pretty serious risks to health).
As recently as 1910-20 in the USA the maternal mortality rate was ~900/100,000 pregnancies! Almost 1 in 1000 women DIED from biblically sanctioned sex. If God hates anal sex he must REALLY hate vaginal sex (and apparently blames Eve for everything).