In estate planning, “equal” isn’t necessarily the same as “fair”. I rarely see an estate plan that does not treat children equally. When I do see inequality, it’s usually because a parent is estranged from one child and leaves him or her nothing.
Dividing an estate into equal shares for each child might seem to be the obvious way to treat children fairly. However, that usually only works if you’ve treated them equally during your lifetime. If you have given more to one child during life, it’s usually smart to level the playing field at death.