There are five daughters and no son in a family. It may be due to
Father produced only $X$ containing sperms
Father produced no sperms at all
$Y$ type sperms are weaker and not effective
By chance each time $X$ sperm fertilized the egg
Assertion : In humans, the gamete contributed by the male determines whether the child produced will be male or female.
Reason : Sex in humans is a polygenic trait depending upon a cumulative effect of some genes on $X-$ chromosome and some on $Y-$ chromosome.
Assertion : In humans, the gamete contributed by the male determines whether the child produced will be male or female.
Reason : Sex in humans is a polygenic trait depending upon a cumulative effect of some genes on $X-$ chromosome and some on $Y-$ chromosome.
Initial clue about the genetic/chromosomal mechanism of sex-determination can be traced back to some of the experiments carried out in
$A$ : $XO$ type sex determination is found in large number of insects.
$R$ : Some of the sperms bear the $X-$chromosome whereas some do not