Mary Kate Olsen has been hospitalized with a kidney infection at the tender age of 21.

The astrology of twins is a fascinating subject, because the psychological issues and conflicts that we all carry within us are usually split between the two twins. Although Mary Kate and Ashley have the same birthdate and essentially the same birthchart, they are quite different which we would expect from fraternal (not identical) twins. But rather than disprove astrology, the difference between them can actually be seen in their birthchart.

The chart of the twins shows the Sun in the sign of the twins – Gemini. Gemini is a natural actor and tends to enjoy taking on roles of all kinds. The twins’ Sun is squared by Jupiter, revealing a confidence and almost reckless nature. The Sun and Jupiter are also aspected by the planet Uranus which reveals their independence and rebellious nature, but they also have the Moon in conservative Virgo.

The Moon in Virgo is much more serious and dislikes the role playing that Gemini is involved in. The Virgo Moon does not like to take the risks that the Sun/Uranus personality does, but prefers to live a life that is more circumspect and geared towards one’s security. To complicate matters even more, their Virgo moon is squared by Saturn, the “celestial taskmaster.” The Virgo Moon squared by Saturn shows an individual with a serious nature who feels that they have to work harder than anyone else in order to have a place at the table.

Without going into a lot of geeky astrological detail, we see two very basic personality types here: the radical bohemian actress who slips in and out of characters and lifestyles and the cautious, security-oriented type who is a hard working and shuns the spotlight. We can see that most recently Mary Kate has played the role of the outgoing twin, rebelling by dropping out of college and taking on a minor role in the hit show “Weeds,” while Ashley has adopted the more cautious and hard-working persona, the brains behind the Olsen’s clothing line. Ashley is the quiet one who hides from photographers while Mary Kate adopts wildly stylized outfits that make her the photographer’s darling.

Mary Kate has dominated the gossip pages with her well-publicized falling out with Paris Hilton over their mutual beau Stavros Niarchos, as well as her documented bout with bulimia and other eating disorders. Mary Kate was the first to drop out of NYU (with Ashley following behind) and Mary Kate seems to be the one that becomes more rebellious and individualistic (Sun/Uranus), whereas Ashley seems to be more isolated but grows stronger and more disciplined (Moon/Saturn). It’s interesting that Mary Kate is left-handed, commonly considered to show that the right side, the creative side, of the brain is dominant. Ashley is right-handed and more logical. Mary Kate’s academic strength is writing whereas Ashley’s is math. Ashley has a history of dating older men which would fit with her association of Saturn, the Lord of Time, and is currently rumored to be dating Lance Armstrong who at 36 is 15 years her senior. True to her rebellious nature, Mary Kate was most recently linked with Max Snow who was evidently disliked by her sister for being a “lowlife.”

At age 21, like everyone does, the twins are going through a double whammy of Saturn and Uranus transits that can be quite challenging. The Saturn cycle creates pressure and puts blocks on our desires, whereas Uranus induces a wild sense of reckless abandon and need for change. Mary Kate seems to be the one to take on the stress of the challenges faced by the twins, and it appears that it is Mary Kate whose health is suffering as well.