My wife and I have two kids: one boy, age 4, and one girl, age 1. We are thinking of buying a pet. What are some good pet options for our family of four? Please include some advantages and disadvantages for each option. 
 Congratulations on your growing family! Pets are often treated like another member of the family and while they can require a lot of work, they can also bring a lot of joy and laughter into your life.

Here are a few options for pets and some advantages and disadvantages for each:

1. Dogs - Dogs can be amazing pets. They are typically very loyal, friendly, and beloved by families all over the world. Dogs can be taught to do tricks like sit, stay, and fetch. There are also over 300 different breeds of dog and they come in all kinds of sizes, ranging from a few lbs (1-2 kg) to over 150 lbs (70 kg). Dogs require quite a bit of work to train and can be very expensive to own due to high veterinary bills. Some dogs can be aggressive, and this is an important factor to consider given that you have two young children. Dogs also typically require access to a yard or regular walking to ensure that they are not going to the bathroom inside. Also, many people are allergic to dogs due to the fact that most dogs shed. If your family members are prone to allergies and are still looking to add a dog to the family, perhaps you should consider a hypoallergenic breed like a Yorkshire Terrier, poodle, or a poodle mix like a Golden Doodle. Dogs typically live between 7-15 years, depending on the breed. 

2. Cats - Cats are another very popular pet option for families. Like dogs, they come in many different breed options but there are far fewer breed options for cats than dogs. Most cats grow to be about 10 lbs (4 kg), but they can range in size from around 5 lbs (2 kg) to 25 lbs (11 kg). Indoor cats typically live between 12-18 years. Cats typically require far less work and are generally more independent than dogs. While most cats can't be trained to do tricks, cats are often lower maintenance than dogs. Cats can often be left alone at the house for a long time. Most cats use a litter box to relieve themselves so they typically don't need regular walks or access to a yard. Like dogs, most cats shed, so allergies and cleaning pet dander can be a nuisance. Cats typically eat less than dogs and often are less expensive to own.

3. Fish - Fish are a popular pet option for families that are looking for a very low maintenance pet that only requires feeding a couple of times per day. Fish typically require water, a clean fish tank and fish food, and that's about it. Some pet fish, like goldfish, can be bought for as little as $10, while exotic fish can cost hundreds or even thousands of dollars. Most pet fish will live up to 2 years if properly cared for, but certain species can live up to 30 years. 

4. Reptiles - Reptiles like snakes, lizards, or iguanas can also be pets. They typically require low maintenance and can live for up to 20-30 years. They require a cage, regular feeding, and are generally easy to take care of. For medical emergencies, they may require specialized veterinarians or doctor's, which can be hard to find.

5. Rodents - rodents like gerbils, hamsters and even mice can be pets as well. They require regular feeding and a small cage, and are typically very easy to take care of. People often include a running wheel in the cage for these small animals so that they can exercise. However, they don't live very long; most rodents only live for a couple of years at most. 

In addition to the list above, there are many other options for pets such as guinea pigs, rabbits, pigs and even exotic options like monkeys. Depending on where you live, there may be certain restrictions on the types of pets that you can own. Please be sure to check with these restrictions before buying your family pet.