In order to prepare for having children, I think it's a good idea to practice with pets.  The order should go like this: 

1. Fish
2. Rodent
3. Cat
4. Dog
5. Human

Each animal requires more responsibility and a bigger financial and time commitment.  Fish are easy.  They just swim around in their bowl.  The only care they really need is daily food and weekly fresh water.  But you can buy an automatic feeder, which essentially reduces your commitment to a weekly water swap.  Not bad. 

Rodents are a little more complicated because their waste products don't float away like a fish's.  So we're talking about a daily feeding and a weekly cage cleaning.  Easy.  And of course there's the automatic feeder option. 

Cats can do one more thing than fish and rodents:  Puke.  In addition to daily feeding (or an automatic feeder) and bi-weekly litter box cleaning, there's the occasional hairball cleanup or "I puke when I get excited" responsibility.  Not pretty. 

Dogs can do one more thing than cats, rodents, and fish:  Make an unbelievable amount of noise for no reason at all.  Also, dogs will eat until they die, so an automatic feeder is out of the question.  Some additional "benefits" of dog ownership:  Dogs need to be walked; dogs slobber; dogs stink; dogs stick their noses in your crotch; dogs stick their tongues in my ear.  I don't like dogs. 

Humans (a.k.a. babies) are the sum of the worst traits of each animal:  They require daily feeding (and not just once or twice a day like an animal).  They puke, often for no reason at all.  They make an unbelievable amount of noise for no reason at all.  Humans need one more thing which dogs, cats, rodents, and fish don't:  Attention/affection.  Otherwise you'll have therapy bills in the future. 

For the record, Wendy and I both had rodents when we were kids.  We had a fish when we were first married, but he went to a better place.  We have two cats.  We're planning on skipping the dog phase because I can't stand dogs.  The next move is to get a real live human.  Someday. #nature

Sometimes, my opinion on a certain topic will change because of information introduced by a trusted third party.  For example, I respect my dad's knowledge of money, so if he tells me it's a good idea to do a certain thing with my money, I'll likely follow his advice.  It's the same with my sister and parenting.  She probably wouldn't actually give advice, but my opinion on parenting changes as I watch her with her kids. 

However, sometimes my opinion on a certain topic won't change regardless of information introduced by a trusted third party, largely because my opinion on the topic is stronger than my trust in that person.  For example, my opinion on drunk driving is that you shouldn't even take a chance.  I'm usually more careful than I legally need to be, but I'd rather be careful than lose my license.  So if a person I respect drinks and drives, my opinion on the topic doesn't change.  Instead, my opinion of the person changes. #psychology