▁baseball ▁players . ▁ ▁The ▁expected ▁distribution ▁of ▁birth s ▁in ▁any ▁given ▁month ▁across ▁a ▁population ▁correl ates ▁closely ▁to ▁the ▁number ▁of ▁days ▁in ▁the ▁month , ▁with ▁February ▁as ▁the ▁short est ▁month ▁having ▁the ▁few est ▁birth s . ▁The ▁first ▁graph ▁shows ▁the ▁distribution ▁of ▁birth s , ▁by ▁month , ▁for ▁the ▁European ▁Union ▁over ▁the ▁ten ▁years ▁from ▁ 2 0 0 0 ▁to ▁ 2 0 0 9 . ▁There ▁is ▁a ▁slight ▁but ▁clearly ▁per cept ible ▁increase ▁in ▁the ▁birth ▁rate ▁in ▁the ▁summer ▁months . ▁ ▁A ▁relative ▁age ▁effect ▁is ▁illustrated ▁in ▁the ▁second ▁graph ▁by ▁the ▁month ▁of ▁birth ▁distribution ▁of ▁over ▁ 4 , 0 0 0 ▁youth ▁players ▁involved ▁in ▁the ▁qual ifying ▁squad s ▁for ▁U 1 7 , ▁U 1 9 ▁and ▁U 2 1 ▁tournament s ▁organ ised ▁by ▁UEFA ▁in ▁ 2 0 1 0 / 1 1 . ▁ ▁Research ▁suggests ▁that ▁individuals ▁born ▁closer ▁to ▁the ▁cut - off ▁date ▁are ▁more ▁likely ▁to ▁play ▁profession ally . ▁ ▁In ▁academ ia ▁ ▁C ut - off ▁dates ▁for ▁academic ▁coh ort ▁struct uring , ▁including ▁the ▁setting ▁of ▁academic ▁years , ▁are ▁usually ▁determined ▁by ▁national ▁education ▁authorities ▁and ▁tend ▁to ▁be ▁based ▁on ▁aut umn ▁start ▁dates , ▁so ▁August ▁or ▁September ▁cut - off ▁dates ▁are ▁common ▁in ▁the ▁Northern ▁Hem is phere ▁and ▁February ▁or ▁March ▁cut - off ▁dates ▁are ▁common ▁in ▁the ▁Southern ▁Hem is phere