why girls can not play in international team of their country?

If you are meaning playing in Men's team, then yes, officially there is no rule that girls shouldn't be in the team. But unofficially that option is not considered purely on the basis of physical differences. In Tennis also women don't compete with Men. I think, if a woman is physically as fit as any other man and can perform at par with Men then she can play in the team. But a woman surely can't bowl around 130 to 140 km per hour or run as quickly as a man can (In athletics too, men have better record than women. It is just a natural difference between a man and a woman. If a girl can perform then she can join the Men's team. In chess, Women compete against men. May be, in that sport it is allowed as it is mainly with respect to Mind and calculation. If women show that they are physically at par with men then they can play alongside men. Let's hope in future that might happen! Happy Mylotting!

This is a very good question. The fact is I would like to see a mixed team of men and woman play cricket. This need not be a test match, but a start can be made with a 2020 competition, and may be they can have six men and six woman in the team. Since people want to make cricket interesting, I hope they do something like this.

There is a womens cricket. You can be the Sachini of womens cricket.