while observing the flowers, Male flowers have a longer stem and are usually found in clusters, while female flowers have a shorter stem and are usually found singly. you need to check the flower shape also. male flowers are generally bell-shaped, while female flowers are more rounded and have a distinctive ovary at the base. Look for fruit development: Female flowers will eventually develop into fruit, while male flowers will not. further, you can use a DNA test that can detect the presence of gender-specific markers.