how can I make a fontsize change on a figure and its children as well?

I have a figure with more than 2 axis and it could have many children in it. How can I change the font size for all parts of the figure? my code is so far:( it doesn't change one of the axis)

 set(gcf,'paperunits','centimeters');

    set(gcf,'paperposition',[2 2 a(1) a(1)*(1/a(2))]);
    textobj=findobj('type','text');
    set(textobj,'fontunits','points');
    set(textobj,'fontsize',5);
    set(findall(gcf,'property','fontsize'),'fontsize',5);
    set(gca,'fontsize',5);
    set(findall(gca,'type','text'),'fontsize',5);
    set(findall(gcf,'type','text'),'fontsize',5);
    new_name=strrep([pathName name],'.fig','.png');
    child=get(gcf,'children');
    for y=1:length(child)
        chi=child(y);
        set(gcf,'chi','fontsize',11);
    end

Answer 1

[Jan]

for y = 1:length(child)
   chi=child(y);
   set(chi, 'fontsize', 11);  % Not set(gcf,'chi','fontsize',11)
end

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