Since 2012, World Down Syndrome Day has been on March 21st. The date is the 21st of the third month as the triplication of the 21st chromosome is what causes Down Syndrome. Each year, a new theme arises. For the year of 2025, the theme is to form the basis of a global campaign. The goal of this day is to help people understand and support those with Down Syndrome better. People who have Down Syndrome usually have an intellectual disability. Around 1 in 800 babies have Down Syndrome. This chromosome defect occurs naturally, as there is no known cause to avoid.