After hearing about Stephen Hawkin's passing, I looked up his astrology birth chart to view any relationship to ALS and the consensus seems to be Mars quincunx Neptune, which he had. (Note; a quincunx is an aspect of 150°, also known as an inconjunct).
Further research tends to indicate that it's not just Mars quincunx another planet that might suggest a medical challenge, but several other factors. These tend to include the ascendant and Saturn either conjunct or in stress aspect.
There is no stated time of birth for Stephen Hawkin, but placing Saturn close to the ascendant, his early years would have been challenging and there is no indication of this. However, if Saturn was in 12th house (late) that would place Uranus (scientific), Lilith (perception) and Jupiter (optimism) all in the first house. Jupiter in the first is extremely optimistic--hence his drive to go on even with ALS. The time of birth for this would be around 1:36 PM on January 8th, 1942.
Stephen Hawkin also had Mars square Mercury which is a significant affect as Mercury is the planet of connections, (the bodily relationship between nervous and neurological activities). There was also a significant number of trines, and grand trines, depending on the number of bodies that are used. He also had the Sun quincunx Chiron, and Venus quincunx North Node, although somewhat wide at 4 degrees. Venus is also square Saturn! (Multiple marriages to younger women?)
On a personal level, I have Mars inconjunct Uranus which may account for my secondary adrenal insufficiency. However, my unidentical twin brother born an hour later at 11:33 pm does not appear to have this problem. His Saturn/Pluto is in the 12th, while mine is in the first close to the Ascendant so Saturn is obviously another factor contributing to this condition.
John F. Kennedy had Mars square Uranus and Saturn (wide) square to the ascendant. He also had Primary Adrenal Insufficiency in the form of Addisons Disease. In addition, Mars and Mercury are both quincunx the ascendant.
In my case it may have been caused by having several head concussions as a child and/or being overdosed with cortisone acetate when I was first diagnosed with this in my forties. I also have a Sun/Jupiter conjunction square to the ascendant/Saturn.
Mars seems to have a significant influence on various areas of the body such as muscles and the adrenal system. This together with Saturn and the ascendant also contributes a crucial role for specific ailments. Perhaps the inconjunct can reveal a more esoteric or rare medical condition, while squares and oppositions, more common conditions. However, as is often the case with special conditions, several factors have to come together to form a unique state.