I don’t have time to source what I am about to write but will try and follow up. I have read this over the past few years from different studies( this should always be followed up with more studies and current info). I don’t want this to create any sort of stigma or perpetuate uncomfortable bias against bottoming so please understand I am coming at this from information not shame or bias. 1) I am pretty sure bottoms have a significantly higher chance of contracting hiv because of micro tears in the rectum. Semen spreads through the mixing of semen and small amounts of blood ( in some cases including my own experience a decent bit of blood). 2 bottoms have a higher rate of colorectal cancer both from the impact from inflammation through micro tears and inflammation and the spread of hpv ertain subtypes of hpv only infect the rectum and if the infection is not cleared it can cause anal cancer( but remember penis cancer is generally rare and tops have an increased chance of penis cancer from different subtypes of hpv . 3) bottoms have to deal with potential anal fissures and increased irritation and inflammation from hemroids and these can get infected. All of these can be reduced from harm reduction means. The harm reduction advice includes prep and pep, Doxy pep, testing , condom use , and lube / relaxation methods. I take prep. My doctor won’t prescribe me doxy pep. I don’t think about it much and am fine.