Andrea Doucet is a sociology professor at Carleton University in Ottawa and author of "Do Men Mother?". He writes at MercatorNet:

British researcher John Bowlby first brought to light the unique importance of the mother-child relationship after he observed a consistent pattern of disrupted relationships and later adult psychopathology (Bowlby, 1944). Children who were deprived of maternal care during extended periods in their early lives “lacked feeling, had superficial relationships, and exhibited hostile or antisocial tendencies” as they developed into adulthood (Kobak, 1999, p. 23).

... Study of Early Child Care concluded that not only was maternal sensitivity and bonding important, it is the strongest, most consistent predictor of a child’s cognitive, social, and emotional development (NICHD, 2003).

... Research findings show that children seem to do best when mothers express love through listening to and communicating with them about thoughts and feelings while monitoring their behavior by setting and enforcing appropriate limits.

... Finally, mothers influence how fathers provide their essential contributions to children’s development.

“An ideal world would be one with a father and a mother. We’d be lying if we pretended that wasn’t true. How can there be an ideal world without a mother for the children?”