As to if he was born like that, assuming it's just his one hand than it's probably "one of those things."
If he has issues with more than one limb then it can be genetic, if there are other issues it can be a known syndrome (which can also be genetic). If it's both arms then it can be drug (eg thalidomide) related.
There are two theories; the first is more popular and often presented as a fact. Do not believe any known American "doctor" website on it.
- Amniotic banding: This theory is where the amniotic fluid forms a band where the limb can't grow through. According to one American "doctor" it also causes clef palate if it's wrapped round the neck
. Stupid.
- A blood clot: This is where a blood clot forma either in the developing limb or the placenta and the limb isn't getting blood to it and the body chooses to stop growing the limb rather than risk the whole foetus.
Interestingly it is much more common (about 2/3)
girls
upper limb
left side
between elbow and wrist.
It is perfectly possible to be born missing your left hand and be clearly should have been left handed. My dd reckons she should have been left handed. I'm not convinced, but I do know people for whom that is definitely true.
If they've been born like that in the 70s that's an interesting time. They would have been encouraged to use a prosthesis. Probably a split hook, but that was round the time that myoelectric became available reach.org.uk/
was the charity set up around campaigning to have myoelectric hands for children.
Children that are born without a hand are less inclined to use a prosthetic than those who lose it-however in the 70s it wasn't often presented as an option.
it also depends on how much of an arm he has:
Below the wrist-not sure when toe to finger transfers came in, I think much more recently than the 70s. They wouldn't have had any prosthesis.
Wrist to elbow-the best to be missing for a prosthesis
Above elbow-becomes a much more complicated device because they need two moving parts. Much less likely to use as very heavy.
I can't think of anything (barring concert pianist-can play the trumpet with right hand only though) that would have been barred for someone;
teacher, customs officer, doctor-I know them all.
If you're talking about adult in the 70s, then things would be different (although the teacher was teaching in the 70s). What I will say is that it won't be thalidomide (or any other drug) if it's just one hand effected. It effected both.
As an adult he might be having other issues relating-back issues (from twisting to use the good hand), shoulder issues (on left hand side if wearing prosthesis), issues with right hand side (overuse of good hand).
Watching this (paraclimber-he's 15yo) might give you an idea of how capable people can be with one hand. he was born like that.