Is there any law prohibiting the use of a home made check?

There is no law prohibiting it in the US.

There are certain standards that modern checks need to meet. These aren't required by law, but banks today generally insist on them. If you are able to meet these standards and print your own checks at home, you are allowed to do so.

One way this is commonly done is with purchased check blanks and check printing software. Office supply stores sell check blanks that fit into standard computer printers. This check paper includes the necessary security features of checks, and using the check printing software, you can print your personal information, including your name & address, your bank's name and address, and your account numbers.

The account numbers on the bottom of the checks are called the MICR code, which stands for Magnetic Ink Character Recognition. Normally, these numbers were printed with special magnetic ink, which was used in automated check reading machines. Checks that you purchase from your bank still use magnetic ink; however, modern check readers are optical, and don't require magnetic ink. So you should be able to print checks with your printer using standard ink/toner, and not have a problem.

In the United States, You can write checks on blank paper or you can create designs, and print checks from home using an Online check writing software, the banks will accept the checks. It is legal and valid.(UCC section-3-104)
The checks must contain the following details:

Account number Routing number Check date Amount in both words and numerics and the signature of the account holder.

you can make a check from your home or office with these details and it becomes both legal and valid.