Michael Otieno still dey remember di pain wey cane give am. No be only for hin hand, but for hin mind too. For hin primary school for western Kenya, cane dey common like blackboard.

"If you late, dem go flog you. If you forget your homework, dem go flog you. No be to teach dem dey do; na to put fear for person body," di 32-year-old accountant wey dey Nairobi tell TRT Afrika.

"Dat fear no make me better student. E just make me dey anxious. E make me believe say violence na di first solution to problem. E take me years to unlearn all dis tin dem."

Otieno no be di only pesin wey carry di scar of corporal punishment enter adulthood. According to new World Health Organisation (WHO) report – "Corporal Punishment of Children: Di Public Health Impact" – physical punishment wey dem dey use correct pikin still dey very common and e dey cause lasting damage for dia health and development.

Di study show say about 1.2 billion pikin for di world dey face physical punishment for dia house every year.

African kontris no dey different, as report from parents show say 77% of pikin for Togo and 64% for Sierra Leone wey dey between 2-14 years old don face corporal punishment di month before di survey.

Schools no be safe place too. Di study show say 70% of pikin for Africa dey experience corporal punishment for school.

"Science don show say corporal punishment get plenty risk for di health of pikin," na wetin Etienne Krug, Director of WHO department for health determinants, talk. "E no get any benefit for di behaviour, development or well-being of di pikin, and e no help parents or society too. Di time don reach to stop dis harmful practice."

Di WHO report explain how corporal punishment dey cause harmful biological reaction, like increase for stress hormone and changes for brain structure and function.

Mental health dey affected too, as di risk of anxiety, depression and low self-esteem dey increase, and e fit follow di person enter adulthood.

Adeola Okonkwo, wey dey work as childcare worker for Lagos, Nigeria, dey always advise parents to use better method to discipline dia pikin.

"Di argument na always, 'Dem flog me and I turn out fine,'" Okonkwo talk. "But we really fine so? Plenty of us dey carry hidden wound wey dey show for how we dey quick vex, how we no fit express emotion, and di way we dey always find approval. We dey confuse respect with fear. We dey break our pikin spirit and we dey call am discipline."

Di WHO study confirm wetin people don dey suspect but no dey talk – say pikin wey dem flog go likely grow to become adult wey go do di same, making violence look normal as way to solve problem.

Dis pikin dem dey also show more aggressive behaviour and dey more likely to involve for violent or criminal act later for life.

Even though many African kontris don ban corporal punishment for school, di study talk say law no dey enough to change di belief wey pipo get about how to discipline pikin for house and school.

WHO talk say law suppose follow with awareness campaign and professional support for parents and teachers.

For pipo like Otieno, di study na proof of wetin dem don dey feel but no fit talk because of society wahala.

"We suppose ask ourselves wetin we really dey teach our pikin," e tell TRT Afrika.

"We dey teach dem wetin good and bad, or we dey teach dem say power dey justify violence? To stop dis no mean say we dey disrespect our culture; e mean say we dey choose better future for di next generation. Science don talk am clear. Di harm dey real. Di time to change don reach."