What are the numbers in parentheses beside my pets stats?

Example: The 20, 21, 22, & 21.
Strength: 101 (20)
Intelligence: 202 (21)
Dexterity: 121 (22)
Agility: 114 (21)

Also, is there any way to breed a pet to have better stats, like breeding two parents with high STR to get an offspring with good STR? I know about the things I can buy in the scale shop to improve these stats, I'm just wondering if there's a way to improve them purely by selective breeding.

The numbers in brackets are the "base stats" of the pets - the stat the pet has at level 0, with no points allocated, no equipment, etc.

You can breed pets for better stats. There are a few ways:

- Offspring's stats will fall somewhere between the base stats of the parents. For example, if one parent had strength of 10 and another strength of 100, the offspring's strength could be anywhere from 10 - 100.

- As you've already noted, Philters can be used - there are Philters in the scale shop and also a Prismatic Philter which can be purchased from the Diamond Shop. The Prismatic Philter gives an extra 200 health and 10 for each stat.

- When you go to hatch an egg, it will prompt you to choose between helping the offspring to hatch and letting it hatch on its own. If you help it hatch, you will get a slight boost to health. If you let it hatch on its own, you'll get a slight boost to one of the other stats - strength, agility, dexterity, intelligence.

Probably worth mentioning at this stage (because it may be your next question), maximum stat-caps at the moment are:
Health 2000
Strength 100
Agility 100
Dexterity 100
Intelligence 100

Hope that helps!

That helped, thanks.