Procreating has to be about the most normal thing a thing can do. Surely it feels Right, and the rightness of it demands your attention. All of this has become possible through offspring. All over the planet, every one's doing it, or trying to do it on some level.
Feeling higher and lower simply (ha) requires an advanced, growing ability to feel and to think. There are immeasurable life forms on this Earth, and we're all fighting for survival, the opportunity to live. Family is just waiting to come into being, if we support it.
The places our minds are able to go are only as limited as our imaginations, it's a capacity of the brain. There are many mental paths of growth, of life. Offspring takes many forms.
It's great to hear of having kids as a very positive, very negative experience, like it has been for you and your children (and probably spouse). It's not hard to see though that many families don't have your same experience, and it amounts to a net increase in (relative) lows, decrease in highs.
Maybe the world would be a different place if taking care of everyone that's already here, first, was more important than having kids? Maybe we could achieve higher highs without needing suffer so many of the lowest lows.