Considering the typical hispanic family is quite large I would assume Jesus had brothers and sisters.
On a more serious note.
It is ridiculous to believe that Mary and Joseph did not have sex and that Mary did not bare more children. Joseph had a young (16-year-old) virgin wife, which I'm sure he took to bed several times a day, and without contraceptives it's likely Mary got pregnant, the natural way.
Mary was a virgin when she had Jesus. God did indeed bless her with a child. That does not mean she was in later years. It says on multiple occasions in the bible that Jesus does have brothers.
"While he was still speaking to the people, behold, his mother and his brothers stood outside, asking to speak to him."
"Then his mother and his brothers came to him, but they could not reach him because of the crowd."
"Is not this the carpenter’s son? Is not his mother called Mary? And are not his brothers James and Joseph and Simon and Judas?"
"But I saw none of the other apostles except James the Lord’s brother."
At the time, having a child without being married was considered wrong. Even if Mary had sex with Joseph and she used the 'holy conception' as a excuse, what other excuse could she give?
After Jesus and the pain she went though giving birth she probably wouldn't want more children. Many people nowadays don't want children after the first and that's with modern day painkillers.
The "Virgin" Mary.
She was a virgin, and remained so throughout her life as my priest told me. He also says that although many old writings/recordings say Jesus had brothers/sisters, but in that time it was common to refer to your cousins as brother and sister, and in some countries they still refer to their cousins like that. So it is likely Jesus just had cousins.