Obviously a male hand will be different from a female hand in its size. Male hands do tend to have fewer palm lines than their female hands. But this does not mean that men have fewer complexities than women.
It may be sometimes true that opposites attract, however largely it is the similarities which govern whether one person has a chance of compatibility with another. Hence it is considered that those features that are similar in each hand offer more chance at true love and friendship.
If a hand print comparison could be done upon meeting another individual, there would be less stress in human relationships, not just in love and marriage.