I've never heard anything about this. I was walking at 6 months because of dislocated hips than had casts and such and had to relearn at 10 months. I'm 27 and no problems yet! In fact, I'm quite certain that all of my 7 siblings were walking around or before 1 yr and no one in my family has had any problems.
Both of my kids walked at 11 months. I think the more detrimental thing would be to prevent your child his/her natural progression of development, but that's just my opinion. How would you prevent a toddler from walking anyway...keep him in a pack n' play all day?
Just seems a bit strange to me.
I would think that the more likely conclusion with this person is that there were hip issues that went unchecked and that's why she walked so early (often happens with dislocated hips, as in my case) and then she didn't have problems until older. Doctors were notoriously not able to screen for those problems in the 70s. My Mom went through an awful time trying to convince the drs. that she knew something was wrong.
Well, that's just my unprofessional, mom-gut opinion, for what it's worth.