Recessive traits can only be expressed with recessive alleles.
Explanation:
According to the law of dominance as proposed by Gregor Mendel, an allele of a gene is capable of masking the phenotypic expression of another allele in the same gene. This allele that masks or that is expressed is called DOMINANT allele while the allele being masked is the RECESSIVE allele.
The dominant allele is responsible for the dominant trait in the organism. Hence, the dominant trait will be expressed when the dominant allele and recessive allele combines (heterozygous). However, the recessive trait is only expressible when the recessive alleles are the same in the gene.
An antibiotic ointment could be used for a woman's vagina lips in case of tearing in natural childbirth which can happen if the baby is say a little too large for the opening as long as not too large to require a caesarian.
