If the father takes antidepressants at conception can the unborn baby be affected or be born with birth defects?

Not likely!: It is highly unlikely that a father taking antidepressants when his wife conceives, would expect any effect on the developing fetus. A large review of women taking antidepressants before and during pregnancy failed to find any major adverse effect. Consider what the effect of a clinical depression, in either mother or father, might have on a developing fetus. Many "self-medicate" w/alcohol, etc.