So after we’ve looked into our nativity to get a good idea of who the people we will be attracted to are like and taken note of our temperament for easy and quick comparison, another step further is to consider the nature of planets, particularly within the contexts of relationships. In the modern tradition, especially in regards to relationships, it is quite common to utilize a separate type of chart calculation, such as Davison or Composite, which attempts to combine two charts either through time and space (Davison) or by taking the average of their planetary positions (Composite). This goes back to the idea of people being puzzle pieces and if we can find the correct one to squeeze together with ours, no matter how rough around the edges it might be, we’ll be destined for a perfect relationship.
Somewhere along the way, the two most important planets to scrutinize became Mars and Venus. Classically, Venus’s nature is to reconcile and unify, so it makes sense that she would be the planet to look to when it comes to people coming together and the stability of that union, that’s what she does, that’s what her nature allows. Mars, on the other hand, makes a lot less sense. His nature is to sever and separate, which is basically the opposite from Venus. Looking for his participation in a relationship should really be more of a cautionary tale than an inspiring sign. Since this has no basis in classical literature or philosophy, there is clearly a modern idea that Mars belongs to sex and sexuality (particularly male) while the classical tradition gives sexuality to Venus who seeks to bring things together.
So where does this idea stem from? The most obvious answer would be the common saying of “men are from Mars, women are from Venus”. While sort of silly in itself, astrologers have taken it pretty seriously. It’s no coincidence that male animals are symbolized by Mars’s glyph while female animals are symbolized by Venus’s, right?
However, it may actually be nothing more than a coincidence. The first scientific use of the glyphs of Mars and Venus was in Carl Linnaeus’s 1751 dissertation on plants Plantae Hybrida (Hybrid Plants) wherein he marked the supposed female parent of a hybrid with the Venus glyph, the male parent with a Mars glyph, and the hybrid itself with a Mercury glyph. Later in his Species Plantarum (1753) he would use the planetary glyphs in more general ways to denote certain characteristics of the plants he documented (such as the Sun glyph for an annual planet and the Jupiter glyph for a perennial plant) as well as continuing to use Mars and Venus to show the gender of particular hybrid plants or plant parts. This trend would later catch on in zoology and biology.
So it seems that a major foundational technique of modern relational astrology has no astrological basis for its philosophy, but rather is based on the workings of an 18th century botanist who doesn’t have any major ties with astrology.
A more classically appropriate method of working within relational astrology would be to identify the major planets in a nativity and see where they fall within the nativity of another, while keeping in mind the context that is given to us by our own nativities.
The major planets would be the Sun, the Moon, and the Lord of Geniture (the planet with the most essential and accidental dignities in the chart). Having these three planets fall within good houses in another person’s chart is a good argument for a successful relationship, especially if they contact that other person’s Sun, Moon, or LoG, but having them fall in bad houses argues stressors.
This is an easy rule of thumb to keep in mind, even if the planets don’t contact one another, seeing where those powerful natal planets fall within the horoscope of another can show major areas of influence an individual can have on another.