Yes, you can register for the BPSC CDPO (Child Development Project Officer) exam if you have a diploma obtained through lateral entry. Let's discuss the details below:

1. Eligibility Criteria:
The Bihar Public Service Commission (BPSC) has set certain eligibility criteria for the CDPO exam. To be eligible for the exam, candidates must fulfill the following criteria:

- Educational Qualification: Candidates must have a Bachelor's degree in any discipline from a recognized university. There are no specific restrictions on the mode of obtaining the degree, whether through lateral entry or regular mode.
- Age Limit: The minimum age limit for general category candidates is 21 years, and the maximum age limit is 37 years. However, there are relaxations in the upper age limit for reserved category candidates as per government rules.

2. Diploma Obtained through Lateral Entry:
Lateral entry is a provision that allows candidates with a diploma to directly enter the second or third year of a degree program, depending on their qualification. If you have obtained a diploma through lateral entry, it means that you have completed the necessary requirements to join a degree program and have entered the program at an advanced stage.

3. Validity of Diploma:
When it comes to the BPSC CDPO exam, the focus is on the candidate's educational qualification, which is a Bachelor's degree. The diploma obtained through lateral entry is considered valid as long as it meets the requirements of the degree program and is recognized by a relevant authority or university.

4. Registration Process:
To register for the BPSC CDPO exam, you need to follow the official registration process as prescribed by the Bihar Public Service Commission. The registration process typically includes the following steps:

- Visit the official BPSC website and navigate to the CDPO exam section.
- Read the official notification and eligibility criteria carefully.
- Fill out the online application form with accurate personal and educational details.
- Upload the required documents, including educational certificates, photograph, and signature.
- Pay the application fee through the available online payment options.
- Submit the application form and take a printout of the confirmation page for future reference.

Conclusion:
In conclusion, if you have a diploma obtained through lateral entry and it meets the requirements of a Bachelor's degree, you are eligible to register for the BPSC CDPO exam. Make sure to carefully read the official notification and follow the prescribed registration process to ensure a smooth application process.