In Jain tradition, the shape of tilak is not a strict scriptural rule based on gender. It is mostly a custom that developed in different communities, families, and regional practices.

Commonly:

• Long tilak is often used for boys/men as a symbol of uprightness, discipline, and spiritual focus.
• Round tilak is often used for girls/women as a symbol of purity, grace, and auspiciousness.

But this is customary, not compulsory in Jain Dharma. Different Jain sects and communities may use different styles, and many Jain practices do not emphasize tilak shape at all.

The main Jain teaching is not the outer shape, but the inner qualities of:

• Ahimsa
• Satya
• Aparigraha
• Self-discipline
• Purity of conduct

So the tilak is mainly a symbolic cultural practice, not a core Jain scriptural distinction between boys and girls.