In some countries myths have developed about what women can and can't do when they have their period - for example, in Madagascar some have grown up believing they can't make mayonnaise while they are menstruating.

One scoutmaster and science teacher, Lahatra, is on a mission to teach Madagascan scouts the truth to make sure boys as well as girls know the facts.

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Filmed by Kenneth Mungai; produced and edited by Clare Spencer.