I apologize for the delay in posting as its been more then a month since my last post but I will be posting regularly in the future.
The issue of the rulers of sex has appeared on a forum I am apart of so I thought it appropriate to repeat the argument here because its quite a controversial issue. Modern and Traditional Astrology have always had some conflict concerning what House has rulership over sex or procreation. On one hand we have the Modern Astrologers who, with very little justification (im sure you can already see who's side I favor so I apologize if you find this biased), state that the 8th House rules over sex. The only justification I can even come up with (and I have yet to see other Modern Astrologers provide a reason as to why this House rules over sex) is that because the 8th House is aligned with Scorpio (as each of the twelve Houses naturally have 12 signs falling into them), and Scorpio has to do with the genitals it must have something to do with sex. Let's analyze this idea for a bit.
The significations of Scorpio include; decaying, decomposition, rotting, things stinking, infected, abounding in worms, & etc. These are not pleasant associations (especially when thinking of sex), however they DO apply to the three areas of the body that Scorpio (and the 8th House) represent, the bladder, genitals and anus/rectum area. So now we understand that yes Scorpio rules over not the function of procreation but the function of waste removal (since genitals are dual purpose). Therefore how is it that the 8th House (which shares similar significations with Scorpio) rules over sex? I have heard many reasons such as "its for darker/passionate sex" but this passion comes from lust which is under the rulership of Venus, not Mars (for Mars has the passion of war, death, destruction).
The significations of Venus however fall quite easily into procreation, in fact all the traditional authors state that Venus also rules over the "seed". Venus has a prime rulership over pleasure and the seeking of pleasure which makes it have a primary placement and rulership under the 5th House who also signifies pleasure. The result of sex is not only pleasure (Venus & 5th House) but also children (another 5th House rulership). In fact the very term "venereal", as venereal diseases, is rooted in the word Venus (meaning of Venus' quality). Its not very hard to understand Venus' connection to procreation & sex (it is one of the most well known qualities of Venus). With this I see much justification in the belief that the 5th House is the House of Sex. We see Venus' rulerships sync with the rulerships of the 5th (hence why she was given joy in that House) and we see in both Venus and the 5th House we see that they both rule over the result of sexual union (pleasure and babies). Therefore it seems impossible, in my opinion, that the 8th House would be associated with sex above the 5th.