You’ll find that Japanese names that end in certain syllables tend to be names for boys while others tend to be names for girls.

Take for example, names that end in roo (郎).  Names that end in roo (郎) tend to be names for baby boys.

Taroo (太郎) = eldest son. Ta (太) = big.  Roo (郎) = son.

Jiroo (二郎)= second son.  Ji (二) = two.  Roo (郎) = son.

Names that end or begin with ta (太) tend to be boy names as well.

Kenta (健太).  Ken (健) = strong.  Ta (太) = big.

Yuuta (勇太).  Yuu (勇) = brave.  Ta (太) = big.

Names that end in ko (子) tend to be female.

Akiko (明子).  Aki (明) = bright.  Ko (子) = child.

Keiko (慶子).  Kei (慶) = celebration.  Ko (子) = child.

Names that end or begin with mi (美) tend to be female as well.

Michiko (美智子).  Mi (美) = beautiful.  Chi (智) = wisdom.  Ko (子).

Yumi (由美).  Yu (由) = reason.  Mi (美) = beautiful.

In general flower names like sakura (桜) = cherry blossoms, tend to be female while masculine names like takeshi (武) = warrior, tend to be for males.