I am predominately right handed but can use my left hand for most any task, including writing as required. While I would not claim to be perfectly ambidexterous; I have cultivated ability in my left arm beginning with that moment of discovery that I was using my right for everything ... sometime in the early 20s or so.
That slight hemi hyprotrophy I have has resulted from favoring my right arm and my late efforts to amend the situation have helped little in the physical appearance department, but greatly in the added functionality I now enjoy when using my left arm.
Today is "International Lefthanders Day" and has been observed since 1976, commencing about a month and a half after I enlisted into the Navy. The day is a promotion of left handedness and those problematic aspects of life in a "right handed" world. Many left handed persons must adapt to using implements designed for right handed people.
It also promotes the special needs of left handed children. I know in the public school system left handed children used to be 'forced' into right handedness by an institutional ignorance for the propriety of people and the way they inherently are.
It is said that left handed people are naturally more intelligent than right handed people. I wonder if that was postulated by a lefty or a righty.