I agree that there are some good mixed schools like Dunman High
but if u checking Ranking of Sec. School u will realise that single
sex sch. like Cedar Girls, Cres. Girls, SJI, IJ schools, SCGS, St
Anthony, Catholic High etc are consistently found in the
list.
These schools don't take in the top PSLE scorers but are able to
get their students to perform well eg my kid's score was 208 but
"O' level she manage to get 13 pts. enough to get her into
JC.
If I'm not wrong, they are all in the top 30 sec schools in S'pore
(that was before they do away with the ranking) & that's why
parents want to put their kids there.