Lets see if I can stir the pot...
For me it began with my grandmother who was on a boat that sunk in the Ohio river in the middle of the night . She hung on to a board for many hours until and she was rescued at daylight. She, rightfully so , was terrified of water which she passed on to my mother.
Thanks, very useful.
Does this means that in the US no one was using rebreathers, before Cousteau-Gagnan compressed air systems appeared on the market?
Here in Europe, instead, and particularly in Italy, the pure-oxygen rebreather was the standard Scuba system until around 1970, when finally compressed-air system superseded those dangerous CC rebreathers.
This possibly explains the profound differences between training systems employed on the two sides of the Atlantic Ocean.
Here, using CC rebreathers, the training had to be long, including deep knowledge about physics, physiology, and the capability of self-controlling breathing and buoyancy. The standard diving course was 6 months long...
Starting directly with "simple to use" compressed air systems, the training in the US was possibly much shorter, or even not-existent. Here no one could even think to start diving without proper "military grade" training...
On the other side, the pure-oxygen rebreather is small, compact, lightweight, and even tiny females could use it easily.
In the Hans Hasse's films you see her girlfriend (and later wife) Lotte swimming very gracefully with her tiny back-mounted rebreather. Here in Italy, the first diving course were organised just after WWII by Luigi Ferraro. His wife was trained as a military frogman during WWII, she was the only female in the Gamma Group, where commander Ferraro did perform many successfull attacks to enemy vessels.
So, albeit long and military grade, diving courses here were initially very "female-friendly"; and it was easy for females to get certified, the CC rebreather is actually better suited for them for a number of physiological and psychological reasons.
When, in the seventies, heavy twin tanks superseded rebreathers, the situation went much worst for females.
When my wife (at the time my girlfriend, she was 16) started her first diving course, in 1976, the did perform very well with the CC rebreather, but she failed when switching to twin tanks, at the end of the course. Without a bladder, she was not capable to keep a proper buoyancy and trim (no BCD, of course, and she was tiny and negative, so even without any weight she was always too heavy with a steel twin tank on her shoulders).
So the advent of air tanks, in the seventies, caused the number of female divers to diminish significantly. Diving became again female-friendly only 10 years later, with the advent of the "American style" training and equipment: a single tank with BCD, an octopus instead of two complete regulators (of which usually the main was a twin-hoses), and shorter and easier courses.
I was a director of a course in 1985 where we had an anomalous number of students (something as 60, instead of the usual 15-20 we had on previous years), and 4/5 of them were females of any age...
This had been entirely impossible 10 years before. During my first course, in 1975, there was only one female, who gave up after just 2 months. The following year there was only my girlfriend, who completed the course but was not certified for failing the exam with the twin tank.
So I think that its important also to understand if the same gender-related dynamics happened also in the US. When diving became a popular sport for females?