We've had more smooth sailing on the sibling rivalry-birth order drama front than stormy, but there certainly have been times when our daughters have clashed.  When our second was born, our oldest was 6--a difficult age to accept the whole mommy-and-daddy-are-busy-with-the-baby-right-now thing.  It had to have hurt--a lot--to hear that after being the center of our world for six years.  As much as we tried not to offer that statement as an excuse when she wanted our attention at an inopportune time or to even generally give off that energy when fried or stretched beyond our max at the moment, it still happened, from time to time, to some degree or another.

I remember worrying about this issue while pregnant with our second daughter. In fact, it was what concerned me the most:  how I was going to manage to give both children enough, if not equal, amounts of my attention?

Through experience I learned it is not possible to make it come out equal in terms of the literal time I've been able to devote to one or the other--a learning which has provided no trifling amount of anguish along the way. Thankfully, I've also learned that my intention to provide for both of their needs as best as I can is what matters.

Balance by definition requires an effort to 'keep or put something in a steady position so it does not fall'.  And effort, by definition being an earnest attempt refers back to my statement about intention, which when pure, will ultimately manifest the end you are seeking.