'Homework for children not parents'
Primary school children from English-speaking homes who attend Welsh-medium schools are less likely to be top performers in core subjects than pupils in English-medium schools.
But they are also less likely to underachieve, according to Welsh government figures.
They look at how 11-year-olds are doing in English, Maths, Science as well as first language Welsh in Welsh schools.
The performance of 25,000 pupils was compared.
Carla Bartlett, is head of Welsh at Ysgol Gyfun Cymer Rhondda in Porth, a Welsh medium secondary school where 99% of pupils are from English-speaking homes.
She said she comes from a similar background herself and says parents looking for their children to move up from primary schools can have worries about issues like homework.