Male gametes are produced more than female gametes in most of the organisms to -
Compensate loss during transport.
Usually female gametes are larger, require much more energy to be produced and are non-motile. On the other hand, male gametes are smaller, require considerably lesser energy to be made and are motile. As the motile species, during gamete transfer the male gametes will try and reach the female gamete. But this requires quite a lot of effort and is inherently risky because most of them are lost in the way. An overwhelming majority of them are thus wasted. One way, most organisms have worked around this problem is to produce the male gametes in large numbers, i.e., several thousand times more than the female gametes. This reduces the risk of failure in gamete transfer and subsequently increases the chance of fertilization.