What is that mean when they said grow balls

Question

its sound bad, but I don't know exactly the meaning

Answer 1

balls are associated with the male genitalia, more specifically the testicles.  Testicles are a symbol of male masculinity, such as aggressiveness, bravery and courage.

So they are saying be more brave and outgoing.

Answer 2

It means be braver or stronger.

Balls are part of a man's genitalia and having them in metaphorical terms means you are manly, so you are strong and brave.

It's used as an offensive term and telling someone to 'grow some balls' means to be more like a man and be stronger.  

Answer 3

If you heard a guy saying this, then the guy is either a perverted g*y or simply in need of severe social company. If a girl said this to you, then she means "be brave" or "be manly". You see, men have testicles, the organs hanging from there crotch like clothes on a clothesline; they resemble balls in shape, hence the phrase.

If you're a female and this phrase was said to you, then you need start shaving your chin hair right now and lose weight.

Answer 4

Grow balls are often considered the brand name "hydroton" its an expanded clay rock that is usually $30 retail for a 50L or 13.2 gallons worth of media.