Why not let in only women refugees and migrants?

I'm mostly talking about Western Europe. I hope we can have a discussion about this because I had this idea a couple weeks ago while watching a video about the recent rise in gang crime in Sweden.

As an American, I've been somewhat following the migration debate taking place in Europe (including the UK), and I've noticed that safety/crime is the biggest concern. For example, Sweden has seen a huge rise in gun violence, especially the gang related type. Two things are often in common among the criminals.

1, They are disproportionately of migrant backgrounds

2, They are almost exclusively male

I don't know about you, but I don't think Syrian women are shooting people in the streets of Malmö or Stockholm. Letting in women ONLY would accomplish two things. It would drastically reduce migrant related crime and importantly, it would help women in the most sexist and oppressive countries live a better life and actually be treated like people with rights. I think it's really awful that women are treated as second class citizens in much of the Middle East and the west could be like a safe haven for many.

What do you think of my idea? I'd like to hear your opinions.