UEFA has decided to take a stance against players parading their children on the pitch at the end of Euro 2016 matches.
The scenes of toddlers in full Wales kit joining their dads on the field at full-time has added to the surprise feel-good story for Chris Coleman's squad.
Wales have upset the odds in their first major competition for 58 years as victories over Slovakia, Russia, Northern Ireland and Belgium have taken them to the semi-final.
However, UEFA has asked for no more on-field family celebrations when Wales play Portugal in Lyon on Wednesday.
UEFA's tournament director Martin Kallen said: "It is a European Championship not a family party."
Kallen added, "a stadium is not the most safe place for small kids" if fans invaded the field, and with ground staff operating machinery on the playing surface.
The UEFA official said: "It is nice pictures. We are not 100 per cent against it but we are cautious."