According to Jain tradition, the answer depends on the sampradāy (tradition):

1. Digambar tradition

- Bhagwan Mahavir is said to have remained brahmachārī (celibate) even while living as a householder. - So in Digambar view: He did not marry and had no children. ( jainknowledge.com)

1. Shwetambar tradition

- Mahavir married Yashodā. - They had one daughter, named Priyadarshanā (also written Priyadarshana / Priyārshanā, sometimes called Anojjā in texts). - So in Shwetambar view: Yes, he had one daughter, no sons. ( jainknowledge.com)

So, whether we say “Mahavir Bhagwan had children” depends on which Jain tradition we are following:

• Digambar: no wife, no children.
• Shwetambar: wife Yashodā, one daughter Priyadarshanā.

You can read a simple life-story of Bhagwan Mahavir including his family details here: