As you draft your estate plan, you certainly can leave equal bequests to all beneficiaries that you name. You can split up all of the tangible assets, like family heirlooms, as evenly as possible. You can split up financial assets perfectly down the middle between two beneficiaries, so they each get an equal share.
But remember that this is an option that you have, not an obligation. You also have the option to use unequal bequests if you would like. You can leave more assets to one beneficiary or leave one sibling a greater amount of financial wealth than another. Do not assume that it has to be perfectly even. You are in control of how you would like to split up your assets, and you can decide if you want to do that evenly or not.
Are there any downsides?
The main downside of using unequal bequests is just that it increases the odds of estate disputes. In some cases, it comes down to sibling rivalry. For instance, one sibling may have thought that their parents always loved their brother or sister more, and an unequal split of assets seems to prove this. In other cases, it is just that people have mismatched expectations, where they assumed things would be equal and they are surprised to find out that they are not.
To avoid both of these issues, it may be a good idea to talk to your beneficiaries in advance when using unequal bequests. Explain that you are not going to split things up equally and talk to them about why you are making this decision. That way, they know what to expect and they can discuss any conflicts or issues with you, rather than finding out about the unequal bequests after you pass away.
Making a comprehensive estate plan is important for the future of your family, so be sure you know what legal steps to take.