Left Handedness or a Disease?
People have always been puzzled by the left handed part of their population. Namely, once people developed writing with their left hand instead of their right one, or preferring their left hand over their right one for many different actions, they were considered strange and unusual, to say the least. Moreover, left handedness was considered a sign of metal problems like retardation, brain damage, dyslexia, autism and many others. There are a lot less people who are left handed than those who use their right hand for most of their daily activities. Amazingly, even 90% of babies starts sucking on their right thumb rather than on their left one. Thus, is left handedness a good or a bad thing, and should all left handed people be worried?
Left Handedness, Causes and Facts
First of all, there are suspicions that left handedness can be transferred genetically, through parents with the same features. So, if both of the parents are left handed, there is a 26% chance that their child will be left handed too. On the other hand, right handed parents have only 9% chances of giving birth to a left handed child. Finally, “mixed” conditions, where each parent uses a different hand to achieve daily goals, these chances are about 19%.
Another theory for left handedness involves testosterone levels. Namely, it is known that excessive testosterone can reduce the growth of the left part of the brain in the child during its mother's pregnancy. Thus, the right brain, which controls the left body functions, takes things into control, so as to replace the left one. Also, science claims to have discovered a left handedness gene, which is likely to cause psychotic mental disorders.
These negative speculations go so far as to consider ultrasound during pregnancy capable of affecting and harming the brain of the fetus, causing left handedness as a side-effect. In fact 30% of mentally retarded children are left handed, while 20% of identical twins with pregnancy complications seem to develop this phenomenon later in life.
Interestingly, using your left hand over your right one for a longer period of time may convert you into a left handed person. It takes about 8 months of use for this to take place. Also, small children tend to imitate their parents or caretakers and their left handedness, developing as left handed themselves. Thus social influence is as important as genetics. All in all, left handedness still remains a mystery hidden deep inside left handed people.