His rising sign was Gemini

The next time I am at the British Library I am so going to look at Conan Doyle's horoscope...

(Needless to say, I am a total astrology skeptic, I do not read my horoscope regularly and as a child I was always very regretful that I was not born a few days later, since Leo seemed a much more attractive personality type than Cancer--my birthday is July 21. However in adult life I am compelled to admit that the Cancer description is indeed more appropriate to my personality, and given the recent swimming obsession and my lifelong love for water it is very suitable to have a watery sign...)

(I am not sure this is so likely to apply to boys as it is to girls, such things were surely not made for or given to boys as commonly, but are you not mildly nostalgic for those childhood diaries that had printed lists of birthstones and which is the paper anniversary at the front?!? I had a little red one, with a lock and key, that was my very precious possession until my brothers pillaged it and scribbled on every page! I was six and they were four, they could not read yet--their wicked friend was the instigator!--so my secrets such as they were remained more or less safe but it gave me a pathological need for privacy that basically could not be satisfied within the confines of family life!)