Natal charts
What does my birth chart say about my sexuality?
Astrologers read sexuality from several points in the birth chart, each answering its own question. Venus describes what draws you in and how you like to be approached. Mars shows how you want and how quickly you catch fire. The Moon covers what you need before you can relax and trust someone. Astrologers also look at Black Moon Lilith, linked with desire a person hides even from themselves, and the eighth house, the house of deep intimacy. Your Sun sign, the one sex horoscopes are written for, decides little here: in our calculation Venus and Mars both sit in the Sun's sign for only 3 people in 100. Venus, Mars and Lilith can almost always be found from the birth date alone; the Moon needs the birth time on about half of all days, and the houses always need it. All of them are free to look up with no sign-up, in the sexuality calculator, the birth chart and the Lilith calculator.
The points astrologers look at
In astrology, sexuality is read from several points of the chart, and each one has its own requirements. Some need only the date of birth; others need the time to within a few minutes.
| Point | What it describes in the tradition | What the calculation needs | Where to look |
|---|---|---|---|
| Venus | what attracts you, which pace and setting you enjoy, how you respond to being pursued | the date; the time matters only on days when Venus changes sign (3.5% of days) | birth chart |
| Mars | how you want, how fast you catch fire, whether you make the first move | the date; the time matters on 1.9% of days | birth chart |
| Moon | what you need to relax and trust, how you experience closeness | date and time: on 43.9% of days the Moon changes sign within 24 hours | birth chart |
| Lilith (Black Moon) | desire a person hides or feels ashamed of | the date; true Lilith needs the time on 7% of days, mean Lilith on 0.4% | Lilith calculator |
| Eighth house | depth of intimacy, trust, willingness to merge with another person | the exact birth time | birth chart with a time |
| Fifth house | flirting, play, pleasure for its own sake | the exact birth time | birth chart with a time |
| Pluto | intensity, obsession, struggles over control in intimacy | the date, but Pluto's sign is shared by everyone born within 12 to 30 years, so only its house and aspects are personal | birth chart |
We calculated the shares of days in this table ourselves. We used Swiss Ephemeris, the library of astronomical tables that also runs our calculators, went through every day from 1950 to 2008 and checked whether each point changes sign between 00:00 and 23:59 UTC. The Ascendant (the sign rising on the eastern horizon at the minute of birth) and the seventh house opposite it are traditionally linked with the kind of partner you choose and how relationships unfold. Astrologers use them less for desire itself.
Why your Sun sign says little about sex
Sex horoscopes are usually written by Sun sign: "Scorpio in bed", "Aries between the sheets". In the tradition the Sun describes character and will in general. Desire belongs to Venus and Mars, and it is rare for both of them to share the Sun's sign.
Venus never gets more than 47 degrees away from the Sun. Seen from Earth, it stays close to it, in the evening after sunset or in the morning before dawn. So your Venus sign is always one of five: your Sun sign, the two signs next to it, or the ones after those.
| Where Venus sits relative to the Sun sign | Share of people |
|---|---|
| Same sign | 24.4% |
| One of the two neighbouring signs | 58.3% |
| Two signs away | 17.2% |
| Further | 0% |
Mars moves on its own and can be in any sign. It shares the Sun's sign for 14.2% of people. That is more than one in twelve, because Mars and the Sun travel across the sky in the same direction and stay close for long stretches. Venus and Mars are both in the Sun's sign for 2.9% of people, and if you add the Moon, all three coincide for 0.3%, three people in a thousand. So for 97 people in 100 at least one of the two planets of desire sits in another sign, and a Sun-sign horoscope describes it by guesswork.
Take someone born with the Sun in Scorpio. Their Venus can be in Virgo, Libra, Scorpio, Sagittarius or Capricorn, and their Mars anywhere at all. With Venus in Libra and Mars in Gemini the picture is airy: interest sparked by conversation, lightness and play. The Scorpio horoscope promises the same person depth, jealousy and control. All the shares in this section come from 100,000 random birth moments between 1950 and 2008.
Venus, Mars and the Moon by element
The tradition groups the twelve signs into four elements: fire (Aries, Leo, Sagittarius), earth (Taurus, Virgo, Capricorn), air (Gemini, Libra, Aquarius) and water (Cancer, Scorpio, Pisces). Before reading a planet's sign, an astrologer looks at its element: the element sets the overall tone and the sign refines it. Each element turns up for about a quarter of people, and equally so for Venus, Mars and the Moon, so there is no rare or "right" element here.
| Element | Venus: what attracts you | Mars: how you want | Moon: what you need to trust |
|---|---|---|---|
| Fire | boldness, excitement, open admiration | fast and direct, taking the initiative; desire flares up at once | attention and enthusiasm; boredom puts desire out |
| Earth | physical presence, reliability, care shown through actions | unhurried and steady, through the senses and a familiar rhythm | stability, physical comfort, predictability |
| Air | conversation, wit, novelty | through words and ideas, curious about trying new things | freedom and conversation; pressure makes it close up |
| Water | emotional depth, tenderness, a sense of merging | through mood: desire grows with trust and can be strong while staying hidden | emotional safety and knowing you will be accepted |
These are the tradition's descriptions. Different schools word them differently, while the direction of each element stays the same.
Reading Venus and Mars together
What matters most is how one person's Venus and Mars combine: what attracts you and how you act on it. In our calculation 28.4% of people have both planets in the same element. Another 23.9% have them in elements the tradition calls allies, fire with air or earth with water. The remaining 47.7% have a different mix: fire with water or earth, air with water or earth.
When the elements match or are allies, taste and action pull the same way: a person wants what attracts them. When the elements diverge, the tradition describes an inner mismatch. Venus in Cancer, for example, is drawn to tenderness and safety, while Mars in Aries acts fast and directly. Such a person may start things and then be thrown by the speed they set themselves. A partner sees mixed signals: pressure one moment, a need for protection the next.
The second layer is the angle between Venus and Mars, which astrologers call an aspect. We measured it with the same tolerances our calculators use. The tolerance, or orb, is how far an angle may drift from exact: 8° for a conjunction and an opposition, 6.5° for a square and a trine, 4.5° for a sextile. 29.6% of people have one of the five major aspects between their own Venus and Mars. The most common is the conjunction (8.9%), read as desire and taste fused together. The square (7.0%) is described as friction between what you like and how you want to act; in sex this tension both excites and wears you out.
The third layer is retrograde motion, the apparent backward movement of a planet as seen from Earth. 7.4% of people are born with Venus retrograde and 9.6% with Mars retrograde. The tradition links it with desire that takes longer to show and is first lived inwardly.
The Moon's part in all this is the conditions. Venus and Mars describe what turns you on; the Moon describes what has to be around you before you want closeness at all: predictability for an earth Moon, conversation for an air Moon, a sense of safety for a water Moon. When the Moon's element differs from Mars's, a person may want quickly and open up slowly.
Lilith
Black Moon Lilith is the apogee of the Moon's orbit, its farthest point from Earth; there is no physical body there. Western tradition links it with repressed desire: what pulls at a person that they will not admit to. Lilith is calculated in two ways. Mean Lilith moves smoothly, true Lilith follows the real wobble of the orbit. In our calculation the two versions fall in different signs for 36.4% of people, so when you read an interpretation it helps to know which version it was written for. The difference is covered in True vs mean Lilith: which one to use, and what its house changes in Lilith in the houses.
Which house rules sex?
Modern astrologers usually point to the 8th house, but the house took on that role late. Greco-Roman astrologers placed sex with the 7th house of partnership, medieval and Renaissance authors moved it to the 5th, the house of pleasure, and only in the twentieth century did it settle in the 8th, where the British astrologer Alan Leo wrote that the house "indicates the sex tendencies". The whole story is told in what the 8th house means in astrology.
The tradition ties the eighth house to deep intimacy, trust and everything a person shares with a partner, from joint money to the willingness to dissolve into someone else. By this logic, planets in the eighth house colour the intimate side of life: Venus adds a longing to merge, Mars adds intensity, Saturn adds caution and slow trust. The fifth house covers the lighter side: flirting, play, pleasure without commitment. Half of all charts have no planet in the 8th house at all (49.8% in our London sample), and astrologers then read the sign on its cusp and the planet that rules that sign.
The houses are built from the Ascendant, which moves into the next sign roughly every two hours. That is why the eighth and fifth houses need an exact birth time, and a calculation from the date alone cannot show them.
Astrologers often bring up Pluto when they talk about sex, yet its sign is shared by a whole generation: everyone born from about 1984 to 1995, for instance, has Pluto in Scorpio. It becomes personal through its house and its close aspects to Venus, Mars or the Moon, and those again need the time.
What you can know without a birth time
If your birth time is unknown, most of the picture is still available. You can check whether a sign is reliable yourself: calculate the chart for 00:00 and for 23:59 on the same day. If a planet's sign stays the same, the time does not matter for it.
| Point | Days when the sign changes within 24 hours | What it means without a time |
|---|---|---|
| Mean Lilith | 0.4% | the sign is almost always known |
| Mars | 1.9% | the sign is almost always known |
| Sun | 3.3% | the sign is almost always known |
| Venus | 3.5% | the sign is almost always known |
| True Lilith | 7.0% | on some days the hour of birth is needed |
| Moon | 43.9% | on almost half of all days the sign depends on the hour |
| Ascendant and houses | every day | unknown without a time |
Many programs fill in noon when the time is unknown. In our calculation that gives the wrong Moon sign in about 11% of the hours of the day, which is roughly one person in nine without a birth time. The sexual compatibility calculator and the Lilith calculator flag any sign that changed on the day of birth.
How to see your own chart
The free birth chart, with no sign-up, lists the sign, degree, house and retrograde status of every planet, Venus, Mars and the Moon included. The houses need an exact birth time. Lilith is calculated separately, in the Lilith calculator: mean and true versions, sign and degree, and the house when the time is known.
To compare yourself with a partner, use the sexual compatibility calculator: it sets both people's Venus, Mars, Moon, Sun and Ascendant side by side and shows how they combine. If one or both birth times are missing, what still holds is explained in Synastry without a birth time. With an account you can get a written reading of your own chart focused on relationships and intimacy; it is covered by the starter bonus you receive when you sign up.
Where the method stops
Everything above describes the astrological tradition. We found no scientific study in which a birth chart predicted sexual behaviour or satisfaction. The closest research tests whether charts predict personality. In 1985 Nature published Shawn Carlson's double-blind test, in which astrologers matched charts to psychological profiles at the level of chance. In 2003 Geoffrey Dean and Ivan Kelly reviewed more than forty such studies and reached the same result.
So a chart works best as a language for talking about yourself. It helps you name what you enjoy and what gets in the way, and then check that against your own experience. A chart cannot tell your orientation, consent or health. If something in your sex life hurts or worries you, that is a question for a doctor or a sex therapist.